Fibers made from copolymers of ethylene/alpha-olefins

ABSTRACT

A fiber is obtainable from or comprises a blend of a propylene based polymer and an ethylene/α-olefin interpolymer characterized by an elastic recovery, Re, in percent at 300 percent strain and 1 cycle and a density, d, in grams/cubic centimeter, wherein the elastic recovery and the density satisfy the following relationship: Re&gt;1481-1629( d ). Such interpolymer can also be characterized by other properties. The fibers made therefrom have a relatively high elastic recovery and a relatively low coefficient of friction. The fibers can be cross-linked, if desired. Woven, knitted or non-woven fabrics can be made from such fibers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. Ser. No. 11/376,873filed Mar. 15, 2006 and also claims priority to U.S. Ser. No. 11/376,835filed on Mar. 15, 2006. For purposes of United States patent practice,the contents of these applications are herein incorporated by referencein their entirety.

FIELD OF THE INVENTION

This invention relates to fibers made from blends of ethylene/α-olefincopolymers with at least one propylene based polymer; methods of makingthe fibers; and products made from the fibers.

BACKGROUND OF THE INVENTION

Fibers are typically classified according to their diameter.Monofilament fibers are generally defined as having an individual fiberdiameter greater than about 15 denier, usually greater than about 30denier per filament. Fine denier fibers generally refer to fibers havinga diameter less than about 15 denier per filament. Microdenier fibersare generally defined as fibers having less than 100 microns indiameter. Fibers can also be classified by the process by which they aremade, such as monofilament, continuous wound fine filament, staple orshort cut fiber, spunbond, and melt blown fibers.

Fibers with excellent elasticity are needed to manufacture a variety offabrics which are used, in turn, to manufacture a myriad of durablearticles, such as sport apparel and furniture upholstery. Elasticity isa performance attribute, and it is one measure of the ability of afabric to conform to the body of a wearer or to the frame of an item.Preferably, the fabric will maintain its conforming fit during repeateduse, extensions and retractions at body and other elevated temperatures(such as those experienced during the washing and drying of the fabric).

Fibers are typically characterized as elastic if they have a highpercent elastic recovery (that is, a low percent permanent set) afterapplication of a biasing force. Ideally, elastic materials arecharacterized by a combination of three important properties: (i) a lowpercent permanent set, (ii) a low stress or load at strain, and (iii) alow percent stress or load relaxation. In other words, elastic materialsare characterized as having the following properties (i) a low stress orload requirement to stretch the material, (ii) no or low relaxing of thestress or unloading once the material is stretched, and (iii) completeor high recovery to original dimensions after the stretching, biasing orstraining is discontinued.

Spandex is a segmented polyurethane elastic material known to exhibitnearly ideal elastic properties. However, spandex is cost prohibitivefor many applications. Also, spandex exhibits poor environmentalresistance to ozone, chlorine and high temperature, especially in thepresence of moisture. Such properties, particularly the lack ofresistance to chlorine, causes spandex to pose distinct disadvantages inapparel applications, such as swimwear and in white garments that aredesirably laundered in the presence of chlorine bleach.

A variety of fibers and fabrics have been made from thermoplastics, suchas polypropylene, highly branched low density polyethylene (LDPE) madetypically in a high pressure polymerization process, linearheterogeneously branched polyethylene (e.g., linear low densitypolyethylene made using Ziegler catalysis), blends of polypropylene andlinear heterogeneously branched polyethylene, blends of linearheterogeneously branched polyethylene, and ethylene/vinyl alcoholcopolymers.

In spite of the advances made in the art, there is a continuing need forpolyolefin-based elastic fibers which are soft and yielding to bodymovement. Preferably, such fibers would have relatively high elasticrecovery and could be made at a relatively high throughput. Moreover, itwould be desirable to form fibers which do not require cumbersomeprocessing steps but still provide soft, comfortable fabrics which arenot tacky.

SUMMARY OF THE INVENTION

The aforementioned needs are met by various aspects of the invention. Inone aspect, the invention relates to a fiber obtainable from orcomprising a blend of at least one propylene based polymer and at leastone ethylene/α-olefin interpolymer, wherein the ethylene/α-olefininterpolymer is characterized by one or more of the following propertiesbefore crosslinking:

(a) having a Mw/Mn from about 1.7 to about 3.5, at least one meltingpoint, Tm, in degrees Celsius, and a density, d, in grams/cubiccentimeter, wherein the numerical values of Tm and d correspond to therelationship:T _(m)>−2002.9+4538.5(d)−2422.2(d)²; or

(b) having a Mw/Mn from about 1.7 to about 3.5, and is characterized bya heat of fusion, ΔH in J/g, and a delta quantity, ΔT, in degreesCelsius defined as the temperature difference between the tallest DSCpeak and the tallest CRYSTAF peak, wherein the numerical values of ΔTand ΔH have the following relationships:ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,ΔT≧48° C. for ΔH greater than 130 J/g,

wherein the CRYSTAF peak is determined using at least 5 percent of thecumulative polymer, and if less than 5 percent of the polymer has anidentifiable CRYSTAF peak, then the CRYSTAF temperature is 30° C.; or

(c) having an elastic recovery, Re, in percent at 300 percent strain and1 cycle measured with a compression-molded film of the interpolymer, andhas a density, d, in grams/cubic centimeter, wherein the numericalvalues of Re and d satisfy the following relationship when theinterpolymer is substantially free of a cross-linked phase:Re>1481-1629(d); or

(d) having a molecular fraction which elutes between 40° C. and 130° C.when fractionated using TREF, characterized in that the fraction has amolar comonomer content of at least 5 percent higher than that of acomparable random ethylene interpolymer fraction eluting between thesame temperatures, wherein said comparable random ethylene interpolymerhas the same comonomer(s) and a melt index, density, and molar comonomercontent (based on the whole polymer) within 10 percent of that of theinterpolymer; or

(e) having a storage modulus at 25° C., G′(25° C.), and a storagemodulus at 100° C., G′(100° C.), wherein the ratio of G′(25° C.) toG′(100° C.) is from about 1:1 to about 10:1;

(f) having at least one molecular fraction which elutes between 40° C.and 130° C. when fractionated using TREF, characterized in that thefraction has a block index of at least 0.5 and up to about 1 and amolecular weight distribution, Mw/Mn, greater than about 1.3; or

(g) having an average block index greater than zero and up to about 1.0and a molecular weight distribution, Mw/Mn, greater than about 1.3.

In another aspect, the invention relates to a fiber obtainable from orcomprising a blend of at least one propylene based polymer and at leastone interpolymer of ethylene and C₃-C₂₀ α-olefin, wherein theinterpolymer has a density from about 0.860 g/cc to about 0.895 g/cc anda compression set at 70° C. of less than about 70%. In some embodiments,the compression set at 70° C. is less than about 60%, less than about50%, less than about 40%, or less than about 30%.

In some embodiments, the interpolymer satisfies the followingrelationship:Re>1491-1629(d); orRe>1501-1629(d); orRe>1511-1629(d).

In other embodiments, the interpolymer has a melt index from about 0.1to about 2000 g/10 minutes, from about 1 to about 1500 g/10 minutes,from about 2 to about 1000 g/10 minutes, from about 5 to about 500 g/10minutes measured according to ASTM D-1238, Condition 190° C./2.16 kg. Insome embodiments, the ethylene/α-olefin interpolymer has a M_(w)/M_(n)from 1.7 to 3.5 and is a random block copolymer comprising at least ahard block and at least a soft block. Preferably, the ethylene/α-olefininterpolymer has a density in the range of about 0.86 to about 0.96 g/ccor about 0.86 to about 0.92 g/cc.

The term “α-olefin” in “ethylene/α-olefin interpolymer” or“ethylene/α-olefin/diene interpolymer” herein refers to C₃ and higherα-olefins. In some embodiments, the α-olefin is styrene, propylene,1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 1-decene, or acombination thereof and the diene is norbornene, 1,5-hexadiene, or acombination.

The fiber is elastic or inelastic. Sometimes, the fiber is crosslinked.In some embodiments, the fiber is crosslinked by photon irradiation,electron beam irradiation, or a crosslinking agent. In some embodiments,the percent of cross-linked polymer is at least 20 percent, such as fromabout 20 percent to about 80 or from about 35 percent to about 50percent, as measured by the weight percent of gels formed. Sometimes,the fiber is a bicomponent fiber. The bicomponent fiber has asheath-core structure; a sea-island structure; a side-by-side structure;a matrix-fibril structure; or a segmented pie structure. The fiber canbe a staple fiber or a binder fiber. In some embodiments, the fiber hascoefficient of friction of less than about 1.2, wherein the interpolymeris not mixed with any filler.

In some embodiments, the fiber has a diameter in the range of about 0.1denier to about 1000 denier and the interpolymer has a melt index fromabout 0.5 to about 2000 and a density from about 0.865 g/cc to about0.955 g/cc. In other embodiments, the fiber has a diameter in the rangeof about 0.1 denier to about 1000 denier and the interpolymer has a meltindex from about 1 to about 2000 and a density from about 0.865 g/cc toabout 0.955 g/cc. In still other embodiments, the fiber has a diameterin the range of about 0.1 denier to about 1000 denier and theinterpolymer has a melt index from about 3 to about 1000 and a densityfrom about 0.865 g/cc to about 0.955 g/cc.

In yet another aspect, the invention relates to a fabric comprising thefibers made in accordance with various embodiments of the invention. Thefabrics can be spunbond; melt blown; gel spun; solution spun; etc. Thefabrics can be elastic or inelastic, woven, non-woven or knitted. Insome embodiments, the fabrics have an MD percent recovery of at least 50percent at 100 percent strain.

In still another aspect, the invention relates to a carded web or yarncomprising the fibers made in accordance with various embodiments of theinvention. The yarn can be covered or not covered. When covered, it maybe covered by cotton yarns or nylon yarns.

In yet still another aspect, the invention relates to a method of makingthe fibers. The method comprises (a) melting a blend of at least onepropylene based polymer and at least one ethylene/α-olefin interpolymer(as described herein); and extruding the blend into a fiber. The fibercan be formed by melting spinning; spunbonding; melt blowing, etc. Insome embodiments, the fabric formed from the fibers is substantiallyfree of roping. Preferably, the fiber is drawn below the peaking meltingtemperature of the interpolymer.

Additional aspects of the invention and characteristics and propertiesof various embodiments of the invention become apparent with thefollowing description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the melting point/density relationship for the inventivepolymers (represented by diamonds) as compared to traditional randomcopolymers (represented by circles) and Ziegler-Natta copolymers(represented by triangles).

FIG. 2 shows plots of delta DSC-CRYSTAF as a function of DSC MeltEnthalpy for various polymers. The diamonds represent randomethylene/octene copolymers; the squares represent polymer examples 1-4;the triangles represent polymer examples 5-9; and the circles representpolymer examples 10-19. The “X” symbols represent polymer examplesA*-F*.

FIG. 3 shows the effect of density on elastic recovery for unorientedfilms made from inventive interpolymers(represented by the squares andcircles) and traditional copolymers (represented by the triangles whichare various AFFINITY® polymers (The Dow Chemical Company). The squaresrepresent inventive ethylene/butene copolymers; and the circlesrepresent inventive ethylene/octene copolymers.

FIG. 4 is a plot of octene content of TREF fractionatedethylene/1-octene copolymer fractions versus TREF elution temperature ofthe fraction for the polymer of Example 5 (represented by the circles)and comparative polymers E and F (represented by the “X” symbols). Thediamonds represent traditional random ethylene/octene copolymers.

FIG. 5 is a plot of octene content of TREF fractionatedethylene/1-octene copolymer fractions versus TREF elution temperature ofthe fraction for the polymer of Example 5 (curve 1) and for comparativeF (curve 2). The squares represent Example F*; and the trianglesrepresent Example 5.

FIG. 6 is a graph of the log of storage modulus as a function oftemperature for comparative ethylene/1-octene copolymer (curve 2) andpropylene/ethylene-copolymer (curve 3) and for two ethylene/1-octeneblock copolymers of the invention made with differing quantities ofchain shuttling agent (curves 1).

FIG. 7 shows a plot of TMA (1 mm) versus flex modulus for some inventivepolymers (represented by the diamonds), as compared to some knownpolymers. The triangles represent various VERSIFY® polymers (The DowChemical Company); the circles represent various random ethylene/styrenecopolymers; and the squares represent various AFFINITY® polymers (TheDow Chemical Company).

FIG. 8 is plot of natural log ethylene mole fraction for randomethylene/α-olefin copolymers as a function of the inverse of DSC peakmelting temperature or ATREF peak temperature. The filled squaresrepresent data points obtained from random homogeneously branchedethylene/α-olefin copolymers in ATREF; and the open squares representdata points obtained from random homogeneously branchedethylene/α-olefin copolymers in DSC. “P” is the ethylene mole fraction;“T” is the temperature in Kelvin.

FIG. 9 is a plot constructed on the basis of the Flory equation forrandom ethylene/α-olefin copolymers to illustrate the definition of“block index.” “A” represents the whole, perfect random copolymer; “B”represents a pure “hard segment”; and “C” represents the whole, perfectblock copolymer having the same comonomer content as “A”. A, B, and Cdefine a triangular area within which most TREF fractions would fall.

FIG. 10 is a schematic of the apparatus for measuring dynamic frictioncoefficients.

FIG. 11 shows dynamic mechanical thermal response of cross-linkedPolymer Example 19A, Example 19B, Example 19K, and Example 19L. Thecurve labeled “19A” represents Polymer Example 19A; the curve labeled“19B” represents Polymer Example 19B; the curve labeled “19K” representsan AFFINITY® EG8100 resin (The Dow Chemical Company); and the curvelabeled “19L” represents a commercial product of 40 denier XLA® fibers(The Dow Chemical Company).

FIG. 12 is a schematic of end-on unwind tension setup.

FIG. 13 shows end-on unwind behavior of fibers from inventive andcomparative examples after: a) storage at 21° C. for 1 day and b)storage at 40° C. for 12 hours. The unit for “unwind tension” is gramforce.

FIG. 14 is a schematic showing the set-up of aspirator/moving screensystem used in some embodiments of the invention.

FIG. 15 shows photos of various webs obtained in nonwoven examples. A isa photo showing the fabric made from Polymer Example 191; B is a photoshowing the fabric made from Polymer Example 190; and C is a photoshowing the fabric made from Polymer Example 19N.

FIG. 16 shows immediate set for various fibers with hysteresis test at100% strain.

FIG. 17 shows retained load at 60% strain for various fibers withhysteresis test at 100% strain.

FIG. 18 shows DSC heating behavior of Fiber 1, Fiber 4 and Fiber 5.

FIG. 19 shows DSC cooling behavior of Fiber 1, Fiber 4 and Fiber 5.

FIG. 20 shows the dynamic mechanical thermal response of Fiber 1 CL,Fiber 4 CL and Fiber 5 CL.

FIG. 21 shows a Transmission Electron Microscopy (TEM) image at about3000× magnification of a sample of Fiber 4 cut perpendicularly.

FIG. 22 shows a Transmission Electron Microscopy (TEM) image at about3000× magnification of a sample of Fiber 4 cut longitudinally.

FIG. 23 shows a Transmission Electron Microscopy (TEM) image at about30000× magnification of the sample shown in FIG. 21.

FIG. 24 shows a Transmission Electron Microscopy (TEM) image at about30000× magnification of the sample shown in FIG. 22.

FIG. 25 shows a Transmission Electron Microscopy (TEM) image at about30000× magnification of a sample of Fiber 4 at the surface level.

FIG. 26 shows a Transmission Electron Microscopy (TEM) image at about30000× magnification of a sample of Fiber 4 at the central level.

FIG. 27 shows a Transmission Electron Microscopy (TEM) image at about30000× magnification of a sample of Fiber 5 cut perpendicularly.

FIG. 28 shows a Transmission Electron Microscopy (TEM) image at about30000× magnification of a sample of Fiber 5 cut longitudinally.

FIG. 29 shows a plot of Melt Strength vs Drawability for two polymercompositions.

FIG. 30 shows a fiber made from Ex. 20 after abrasion resistancetesting.

FIG. 31 shows a fiber made from a blend of Ex. 20 and polypropyleneafter abrasion resistance testing.

FIG. 32 shows the results of TMA testing for three fibers.

DETAILED DESCRIPTION OF THE INVENTION

General Definitions

“Fiber” means a material in which the length to diameter ratio isgreater than about 10. Fiber is typically classified according to itsdiameter. Filament fiber is generally defined as having an individualfiber diameter greater than about 15 denier, usually greater than about30 denier per filament. Fine denier fiber generally refers to a fiberhaving a diameter less than about 15 denier per filament. Microdenierfiber is generally defined as fiber having a diameter less than about100 microns denier per filament.

“Filament fiber” or “monofilament fiber” means a continuous strand ofmaterial of indefinite (i.e., not predetermined) length, as opposed to a“staple fiber” which is a discontinuous strand of material of definitelength (i.e., a strand which has been cut or otherwise divided intosegments of a predetermined length).

“Elastic” means that a fiber will recover at least about 50 percent ofits stretched length after the first pull and after the fourth to 100%strain (doubled the length). Elasticity can also be described by the“permanent set” of the fiber. Permanent set is the converse ofelasticity. A fiber is stretched to a certain point and subsequentlyreleased to the original position before stretch, and then stretchedagain. The point at which the fiber begins to pull a load is designatedas the percent permanent set. “Elastic materials” are also referred toin the art as “elastomers” and “elastomeric”. Elastic material(sometimes referred to as an elastic article) includes the polymer orblend of polymers itself as well as, but not limited to, the polymer orthe blend of polymers in the form of a fiber, film, strip, tape, ribbon,sheet, coating, molding and the like. The preferred elastic material isfiber. The elastic material can be either cured or uncured, radiated orun-radiated, and/or crosslinked or uncrosslinked.

“Nonelastic material” means a material, e.g., a fiber, that is notelastic as defined above.

“Substantially crosslinked” and similar terms mean that the polymer orthe blend of polymers, shaped or in the form of an article, has xyleneextractables of less than or equal to 70 weight percent (i.e., greaterthan or equal to 30 weight percent gel content), preferably less than orequal to 40 weight percent (i.e., greater than or equal to 60 weightpercent gel content). Xylene extractables (and gel content) aredetermined in accordance with ASTM D-2765.

“Homofil fiber” means a fiber that has a single polymer region ordomain, and that does not have any other distinct polymer regions (as dobicomponent fibers).

“Bicomponent fiber” means a fiber that has two or more distinct polymerregions or domains. Bicomponent fibers are also known as conjugated ormulticomponent fibers. The polymers are usually different from eachother although two or more components may comprise the same polymer. Thepolymers are arranged in substantially distinct zones across thecross-section of the bicomponent fiber, and usually extend continuouslyalong the length of the bicomponent fiber. The configuration of abicomponent fiber can be, for example, a sheath/core arrangement (inwhich one polymer is surrounded by another), a side by side arrangement,a pie arrangement or an “islands-in-the sea” arrangement. Bicomponentfibers are further described in U.S. Pat. Nos. 6,225,243; 6,140,442;5,382,400; 5,336,552 and 5,108,820.

“Meltblown fibers” are fibers formed by extruding a molten thermoplasticpolymer composition through a plurality of fine, usually circular, diecapillaries as molten threads or filaments into converging high velocitygas streams (e.g. air) which function to attenuate the threads orfilaments to reduced diameters. The filaments or threads are carried bythe high velocity gas streams and deposited on a collecting surface toform a web of randomly dispersed fibers with average diameters generallysmaller than 10 microns.

“Meltspun fibers” are fibers formed by melting at least one polymer andthen drawing the fiber in the melt to a diameter (or other cross-sectionshape) less than the diameter (or other cross-section shape) of the die.

“Spunbond fibers” are fibers formed by extruding a molten thermoplasticpolymer composition as filaments through a plurality of fine, usuallycircular, die capillaries of a spinneret. The diameter of the extrudedfilaments is rapidly reduced, and then the filaments are deposited ontoa collecting surface to form a web of randomly dispersed fibers withaverage diameters generally between about 7 and about 30 microns.

“Nonwoven” means a web or fabric having a structure of individual fibersor threads which are randomly interlaid, but not in an identifiablemanner as is the case of a knitted fabric. The elastic fiber inaccordance with embodiments of the invention can be employed to preparenonwoven structures as well as composite structures of elastic nonwovenfabric in combination with nonelastic materials.

“Yarn” means a continuous length of twisted or otherwise entangledfilaments which can be used in the manufacture of woven or knittedfabrics and other articles. Yarn can be covered or uncovered. Coveredyarn is yarn at least partially wrapped within an outer covering ofanother fiber or material, typically a natural fiber such as cotton orwool.

“Polymer” means a polymeric compound prepared by polymerizing monomers,whether of the same or a different type. The generic term “polymer”embraces the terms “homopolymer,” “copolymer,” “terpolymer” as well as“interpolymer.”

“Propylene based polymer” means a polymeric compound comprising at least50 wt % propylene.

“Interpolymer” means a polymer prepared by the polymerization of atleast two different types of monomers. The generic term “interpolymer”includes the term “copolymer” (which is usually employed to refer to apolymer prepared from two different monomers) as well as the term“terpolymer” (which is usually employed to refer to a polymer preparedfrom three different types of monomers). It also encompasses polymersmade by polymerizing four or more types of monomers.

The term “ethylene/α-olefin interpolymer” generally refers to polymerscomprising ethylene and an α-olefin having 3 or more carbon atoms.Preferably, ethylene comprises the majority mole fraction of the wholepolymer, i.e., ethylene comprises at least about 50 mole percent of thewhole polymer. More preferably, ethylene comprises at least about 60mole percent, at least about 70 mole percent, or at least about 80 molepercent, with the substantial remainder of the whole polymer comprisingat least one other comonomer that is preferably an α-olefin having 3 ormore carbon atoms. For many ethylene/octene copolymers, the preferredcomposition comprises an ethylene content greater than about 80 molepercent of the whole polymer and an octene content of from about 10 toabout 15, preferably from about 15 to about 20 mole percent of the wholepolymer. In some embodiments, the ethylene/α-olefin interpolymers do notinclude those produced in low yields or in a minor amount or as aby-product of a chemical process. While the ethylene/α-olefininterpolymers can be blended with one or more polymers, the as-producedethylene/α-olefin interpolymers are substantially pure and oftencomprise a major component of the reaction product of a polymerizationprocess.

The ethylene/α-olefin interpolymers comprise ethylene and one or morecopolymerizable α-olefin comonomers in polymerized form, characterizedby multiple blocks or segments of two or more polymerized monomer unitsdiffering in chemical or physical properties. That is, theethylene/α-olefin interpolymers are block interpolymers, preferablymulti-block interpolymers or copolymers. The terms “interpolymer” and“copolymer” are used interchangeably herein. In some embodiments, themulti-block copolymer can be represented by the following formula:(AB)_(n)where n is at least 1, preferably an integer greater than 1, such as 2,3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or higher, “A”represents a hard block or segment and “B” represents a soft block orsegment. Preferably, As and Bs are linked in a substantially linearfashion, as opposed to a substantially branched or substantiallystar-shaped fashion. In other embodiments, A blocks and B blocks arerandomly distributed along the polymer chain. In other words, the blockcopolymers usually do not have a structure as follows.AAA-AA-BBB-BB

In still other embodiments, the block copolymers do not usually have athird type of block, which comprises different comonomer(s). In yetother embodiments, each of block A and block B has monomers orcomonomers substantially randomly distributed within the block. In otherwords, neither block A nor block B comprises two or more sub-segments(or sub-blocks) of distinct composition, such as a tip segment, whichhas a substantially different composition than the rest of the block.

The multi-block polymers typically comprise various amounts of “hard”and “soft” segments. “Hard” segments refer to blocks of polymerizedunits in which ethylene is present in an amount greater than about 95weight percent, and preferably greater than about 98 weight percentbased on the weight of the polymer. In other words, the comonomercontent (content of monomers other than ethylene) in the hard segmentsis less than about 5 weight percent, and preferably less than about 2weight percent based on the weight of the polymer. In some embodiments,the hard segments comprise all or substantially all ethylene. “Soft”segments, on the other hand, refer to blocks of polymerized units inwhich the comonomer content (content of monomers other than ethylene) isgreater than about 5 weight percent, preferably greater than about 8weight percent, greater than about 10 weight percent, or greater thanabout 15 weight percent based on the weight of the polymer. In someembodiments, the comonomer content in the soft segments can be greaterthan about 20 weight percent, greater than about 25 weight percent,greater than about 30 weight percent, greater than about 35 weightpercent, greater than about 40 weight percent, greater than about 45weight percent, greater than about 50 weight percent, or greater thanabout 60 weight percent.

The soft segments can often be present in a block interpolymer fromabout 1 weight percent to about 99 weight percent of the total weight ofthe block interpolymer, preferably from about 5 weight percent to about95 weight percent, from about 10 weight percent to about 90 weightpercent, from about 15 weight percent to about 85 weight percent, fromabout 20 weight percent to about 80 weight percent, from about 25 weightpercent to about 75 weight percent, from about 30 weight percent toabout 70 weight percent, from about 35 weight percent to about 65 weightpercent, from about 40 weight percent to about 60 weight percent, orfrom about 45 weight percent to about 55 weight percent of the totalweight of the block interpolymer. Conversely, the hard segments can bepresent in similar ranges. The soft segment weight percentage and thehard segment weight percentage can be calculated based on data obtainedfrom DSC or NMR. Such methods and calculations are disclosed in U.S.patent application Ser. No. 11/376,835 filed on Mar. 15, 2006, thedisclosure of which is incorporated by reference herein in its entirety.

The term “crystalline” if employed, refers to a polymer that possesses afirst order transition or crystalline melting point (Tm) as determinedby differential scanning calorimetry (DSC) or equivalent technique. Theterm may be used interchangeably with the term “semicrystalline”. Theterm “amorphous” refers to a polymer lacking a crystalline melting pointas determined by differential scanning calorimetry (DSC) or equivalenttechnique.

The term “multi-block copolymer” or “segmented copolymer” refers to apolymer comprising two or more chemically distinct regions or segments(referred to as “blocks”) preferably joined in a linear manner, that is,a polymer comprising chemically differentiated units which are joinedend-to-end with respect to polymerized ethylenic functionality, ratherthan in pendent or grafted fashion. In a preferred embodiment, theblocks differ in the amount or type of comonomer incorporated therein,the density, the amount of crystallinity, the crystallite sizeattributable to a polymer of such composition, the type or degree oftacticity (isotacetic or syndiotacetic), regio-regularity orregio-irregularity, the amount of branching, including long chainbranching or hyper-branching, the homogeneity, or any other chemical orphysical property. The multi-block copolymers are characterized byunique distributions of both polydispersity index (PDI or Mw/Mn), blocklength distribution, and/or block number distribution due to the uniqueprocess making of the copolymers. More specifically, when produced in acontinuous process, the polymers desirably possess PDI from 1.7 to 2.9,preferably from 1.8 to 2.5, more preferably from 1.8 to 2.2, and mostpreferably from 1.8 to 2.1. When produced in a batch or semi-batchprocess, the polymers possess PDI from 1.0 to 2.9, preferably from 1.3to 2.5, more preferably from 1.4 to 2.0, and most preferably from 1.4 to1.8.

In the following description, all numbers disclosed herein areapproximate values, regardless whether the word “about” or “approximate”is used in connection therewith. Depending upon the context in whichsuch values are described herein, and unless specifically statedotherwise, such values may vary by 1 percent, 2 percent, 5 percent, or,sometimes, 10 to 20 percent. Whenever a numerical range with a lowerlimit, R^(L) and an upper limit, R^(U), is disclosed, any number fallingwithin the range is specifically disclosed. In particular, the followingnumbers within the range are specifically disclosed: R=R^(L)+k*(R^(U)−R^(L)), wherein k is a variable ranging from 1 percent to 100percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3percent, 4 percent, 5 percent, . . . , 50 percent, 51 percent, 52percent, . . . , 95 percent, 96 percent, 97 percent, 98 percent, 99percent, or 100 percent. Moreover, any numerical range defined by two Rnumbers as defined in the above is also specifically disclosed. When aparticular reference is mentioned (e.g., a patent or journal article),it should be understood that such reference is incorporated by referenceherein in its entirety, regardless of whether such wording is used inconnection with it.

Embodiments of the invention provide, fibers obtainable from orcomprising a blend of at least one propylene based polymer with at leastone ethylene/α-olefin interpolymer that has unique properties, andfabrics and other products made from such fibers. The fibers may havegood abrasion resistance; low coefficient of friction; high upperservice temperature; high recovery/retractive force; low stressrelaxation (high and low temperatures); soft stretch; high elongation atbreak; inert: chemical resistance; and/or UV resistance. The fibers canbe melt spun at a relatively high spin rate and lower temperature. Inaddition, the fibers are less sticky, resulting in better unwindperformance and better shelf life, and the fabrics made from the fibersare substantially free of roping (i.e., fiber bundling). Because thefibers can be spun at a higher spin rate, the fibers' productionthroughput is high. Such fibers also have broad formation windows andbroad processing windows.

Ethylene/α-Olefin Interpolymers

The ethylene/α-olefin interpolymers used in embodiments of the invention(also referred to as “inventive interpolymer” or “inventive polymer”)comprise ethylene and one or more copolymerizable α-olefin comonomers inpolymerized form, characterized by multiple blocks or segments of two ormore polymerized monomer units differing in chemical or physicalproperties (block interpolymer), preferably a multi-block copolymer. Theethylene/α-olefin interpolymers are characterized by one or more of theaspects described as follows.

In one aspect, the ethylene/α-olefin interpolymers used in thecushioning net structures provided herein have a M_(w)/M_(n) from about1.7 to about 3.5 and at least one melting point, T_(m), in degreesCelsius and density, d, in grams/cubic centimeter, wherein the numericalvalues of the variables correspond to the relationship:T _(m)>−2002.9+4538.5(d)−2422.2(d)₂, and preferablyT _(m)≧−6288.1+13141(d)−6720.3(d)₂, and more preferablyT _(m)≧858.91−1825.3(d)+1112.8(d)².

Such melting point/density relationship is illustrated in FIG. 1. Unlikethe traditional random copolymers of ethylene/α-olefins whose meltingpoints decrease with decreasing densities, the inventive interpolymers(represented by diamonds) exhibit melting points substantiallyindependent of the density, particularly when density is between about0.87 g/cc to about 0.95 g/cc. For example, the melting points of suchpolymers are in the range of about 110° C. to about 130° C. when densityranges from 0.875 g/cc to about 0.945 g/cc. In some embodiments, themelting point of such polymers are in the range of about 115° C. toabout 125° C. when density ranges from 0.875 g/cc to about 0.945 g/cc.

In another aspect, the ethylene/α-olefin interpolymers comprise, inpolymerized form, ethylene and one or more α-olefins and arecharacterized by a ΔT, in degree Celsius, defined as the temperature forthe tallest Differential Scanning Calorimetry (“DSC”) peak minus thetemperature for the tallest Crystallization Analysis Fractionation(“CRYSTAF”) peak and a heat of fusion in J/g, ΔH, and ΔT and ΔH satisfythe following relationships:ΔT>−0.1299(ΔH)+62.81, and preferablyΔT≧−0.1299(ΔH)+64.38, and more preferablyΔT≧−0.1299(ΔH)+65.95,for ΔH up to 130 J/g. Moreover, ΔT is equal to or greater than 48° C.for ΔH greater than 130 J/g. The CRYSTAF peak is determined using atleast 5 percent of the cumulative polymer (that is, the peak mustrepresent at least 5 percent of the cumulative polymer), and if lessthan 5 percent of the polymer has an identifiable CRYSTAF peak, then theCRYSTAF temperature is 30° C., and ΔH is the numerical value of the heatof fusion in J/g. More preferably, the highest CRYSTAF peak contains atleast 10 percent of the cumulative polymer. FIG. 2 shows plotted datafor inventive polymers as well as comparative examples. Integrated peakareas and peak temperatures are calculated by the computerized drawingprogram supplied by the instrument maker. The diagonal line shown forthe random ethylene octene comparative polymers corresponds to theequation ΔT=−0.1299 (ΔH)+62.81.

In yet another aspect, the ethylene/α-olefin interpolymers have amolecular fraction which elutes between 40° C. and 130° C. whenfractionated using Temperature Rising Elution Fractionation (“TREF”),characterized in that said fraction has a molar comonomer contenthigher, preferably at least 5 percent higher, more preferably at least10 percent higher, than that of a comparable random ethyleneinterpolymer fraction eluting between the same temperatures, wherein thecomparable random ethylene interpolymer contains the same comonomer(s),and has a melt index, density, and molar comonomer content (based on thewhole polymer) within 10 percent of that of the block interpolymer.Preferably, the Mw/Mn of the comparable interpolymer is also within 10percent of that of the block interpolymer and/or the comparableinterpolymer has a total comonomer content within 10 weight percent ofthat of the block interpolymer.

In still another aspect, the ethylene/α-olefin interpolymers arecharacterized by an elastic recovery, Re, in percent at 300 percentstrain and 1 cycle measured on a compression-molded film of anethylene/α-olefin interpolymer, and have a density, d, in grams/cubiccentimeter, wherein the numerical values of Re and d satisfy thefollowing relationship when ethylene/α-olefin interpolymer issubstantially free of a cross-linked phase:Re>1481-1629(d); and preferablyRe≧1491-1629(d); and more preferablyRe≧1501-1629(d); and even more preferablyRe≧1511-1629(d).

FIG. 3 shows the effect of density on elastic recovery for unorientedfilms made from certain inventive interpolymers and traditional randomcopolymers. For the same density, the inventive interpolymers havesubstantially higher elastic recoveries.

In some embodiments, the ethylene/α-olefin interpolymers have a tensilestrength above 10 MPa, preferably a tensile strength ≧11 MPa, morepreferably a tensile strength ≧13 MPa and/or an elongation at break ofat least 600 percent, more preferably at least 700 percent, highlypreferably at least 800 percent, and most highly preferably at least 900percent at a crosshead separation rate of 11 cm/minute.

In other embodiments, the ethylene/α-olefin interpolymers have (1) astorage modulus ratio, G′(25° C.)/G′(100° C.), of from 1 to 50,preferably from 1 to 20, more preferably from 1 to 10; and/or (2) a 70°C. compression set of less than 80 percent, preferably less than 70percent, especially less than 60 percent, less than 50 percent, or lessthan 40 percent, down to a compression set of 0 percent.

In still other embodiments, the ethylene/α-olefin interpolymers have a70° C. compression set of less than 80 percent, less than 70 percent,less than 60 percent, or less than 50 percent. Preferably, the 70° C.compression set of the interpolymers is less than 40 percent, less than30 percent, less than 20 percent, and may go down to about 0 percent.

In some embodiments, the ethylene/α-olefin interpolymers have a heat offusion of less than 85 J/g and/or a pellet blocking strength of equal toor less than 100 pounds/foot² (4800 Pa), preferably equal to or lessthan 50 lbs/ft² (2400 Pa), especially equal to or less than 5 lbs/ft²(240 Pa), and as low as 0 lbs/ft² (0 Pa).

In other embodiments, the ethylene/α-olefin interpolymers comprise, inpolymerized form, at least 50 mole percent ethylene and have a 70° C.compression set of less than 80 percent, preferably less than 70 percentor less than 60 percent, most preferably less than 40 to 50 percent anddown to close to zero percent.

In some embodiments, the multi-block copolymers possess a PDI fitting aSchultz-Flory distribution rather than a Poisson distribution. Thecopolymers are further characterized as having both a polydisperse blockdistribution and a polydisperse distribution of block sizes andpossessing a most probable distribution of block lengths. Preferredmulti-block copolymers are those containing 4 or more blocks or segmentsincluding terminal blocks. More preferably, the copolymers include atleast 5, 10 or 20 blocks or segments including terminal blocks.

Comonomer content may be measured using any suitable technique, withtechniques based on nuclear magnetic resonance (“NMR”) spectroscopypreferred. Moreover, for polymers or blends of polymers havingrelatively broad TREF curves, the polymer desirably is firstfractionated, using TREF, into fractions each having an elutedtemperature range of 10° C. or less. That is, each eluted fraction has acollection temperature window of 10° C. or less. Using this technique,said block interpolymers have at least one such fraction having a highermolar comonomer content than a corresponding fraction of the comparableinterpolymer.

Preferably, for interpolymers of ethylene and 1-octene, the blockinterpolymer has a comonomer content of the TREF fraction elutingbetween 40 and 130° C. greater than or equal to the quantity (−0.2013)T+20.07, more preferably greater than or equal to the quantity (−0.2013)T+21.07, where T is the numerical value of the peak elution temperatureof the TREF fraction being compared, measured in ° C.

FIG. 4 graphically depicts an embodiment of the block interpolymers ofethylene and 1-octene where a plot of the comonomer content versus TREFelution temperature for several comparable ethylene/1-octeneinterpolymers (random copolymers) are fit to a line representing(−0.2013) T+20.07 (solid line). The line for the equation (−0.2013)T+21.07 is depicted by a dotted line. Also depicted are the comonomercontents for fractions of several block ethylene/1-octene interpolymersof the invention (multi-block copolymers). All of the block interpolymerfractions have significantly higher 1-octene content than either line atequivalent elution temperatures. This result is characteristic of theinventive interpolymer and is believed to be due to the presence ofdifferentiated blocks within the polymer chains, having both crystallineand amorphous nature.

FIG. 5 graphically displays the TREF curve and comonomer contents ofpolymer fractions for Example 5 and comparative F to be discussed below.The peak eluting from 40 to 130° C., preferably from 60° C. to 95° C.for both polymers is fractionated into three parts, each part elutingover a temperature range of less than 10° C. Actual data for Example 5is represented by triangles. The skilled artisan can appreciate that anappropriate calibration curve may be constructed for interpolymerscontaining different comonomers and a line used as a comparison fittedto the TREF values obtained from comparative interpolymers of the samemonomers, preferably random copolymers made using a metallocene or otherhomogeneous catalyst composition. Inventive interpolymers arecharacterized by a molar comonomer content greater than the valuedetermined from the calibration curve at the same TREF elutiontemperature, preferably at least 5 percent greater, more preferably atleast 10 percent greater.

In addition to the above aspects and properties described herein, theinventive polymers can be characterized by one or more additionalcharacteristics. In one aspect, the inventive polymer is an olefininterpolymer, preferably comprising ethylene and one or morecopolymerizable comonomers in polymerized form, characterized bymultiple blocks or segments of two or more polymerized monomer unitsdiffering in chemical or physical properties (blocked interpolymer),most preferably a multi-block copolymer, said block interpolymer havinga molecular fraction which elutes between 40° C. and 130° C., whenfractionated using TREF increments, characterized in that said fractionhas a molar comonomer content higher, preferably at least 5 percenthigher, more preferably at least 10, 15, 20 or 25 percent higher, thanthat of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer comprises the same comonomer(s), preferably it is the samecomonomer(s), and a melt index, density, and molar comonomer content(based on the whole polymer) within 10 percent of that of the blockedinterpolymer. Preferably, the Mw/Mn of the comparable interpolymer isalso within 10 percent of that of the blocked interpolymer and/or thecomparable interpolymer has a total comonomer content within 10 weightpercent of that of the blocked interpolymer.

Preferably, the above interpolymers are interpolymers of ethylene and atleast one alpha-olefin, especially those interpolymers having a wholepolymer density from about 0.855 to about 0.935 g/cm³, and moreespecially for polymers having more than about 1 mole percent comonomer,the blocked interpolymer has a comonomer content of the TREF fractioneluting between 40 and 130° C. greater than or equal to the quantity(−0.1356) T+13.89, more preferably greater than or equal to the quantity(−0.1356) T+14.93, and most preferably greater than or equal to thequantity (−0.2013)T+21.07, where T is the numerical value of the peakATREF elution temperature of the TREF fraction being compared, measuredin ° C.

Preferably, for the above interpolymers of ethylene and at least onealpha-olefin especially those interpolymers having a whole polymerdensity from about 0.855 to about 0.935 g/cm³, and more especially forpolymers having more than about 1 mole percent comonomer, the blockedinterpolymer has a comonomer content of the TREF fraction elutingbetween 40 and 130° C. greater than or equal to the quantity (−0.2013)T+20.07, more preferably greater than or equal to the quantity (−0.2013)T+21.07, where T is the numerical value of the peak elution temperatureof the TREF fraction being compared, measured in ° C.

In still another aspect, the inventive polymer is an olefininterpolymer, preferably comprising ethylene and one or morecopolymerizable comonomers in polymerized form, characterized bymultiple blocks or segments of two or more polymerized monomer unitsdiffering in chemical or physical properties (blocked interpolymer),most preferably a multi-block copolymer, said block interpolymer havinga molecular fraction which elutes between 40° C. and 130° C., whenfractionated using TREF increments, characterized in that every fractionhaving a comonomer content of at least about 6 mole percent, has amelting point greater than about 100° C. For those fractions having acomonomer content from about 3 mole percent to about 6 mole percent,every fraction has a DSC melting point of about 110° C. or higher. Morepreferably, said polymer fractions, having at least 1 mol percentcomonomer, has a DSC melting point that corresponds to the equation:Tm≧(−5.5926)(mol percent comonomer in the fraction)+135.90.

In yet another aspect, the inventive polymer is an olefin interpolymer,preferably comprising ethylene and one or more copolymerizablecomonomers in polymerized form, characterized by multiple blocks orsegments of two or more polymerized monomer units differing in chemicalor physical properties (blocked interpolymer), most preferably amulti-block copolymer, said block interpolymer having a molecularfraction which elutes between 40° C. and 130° C., when fractionatedusing TREF increments, characterized in that every fraction that has anATREF elution temperature greater than or equal to about 76° C., has amelt enthalpy (heat of fusion) as measured by DSC, corresponding to theequation:Heat of fusion (J/gm)≦(3.1718)(ATREF elution temperature inCelsius)−136.58,

The inventive block interpolymers have a molecular fraction which elutesbetween 40° C. and 130° C., when fractionated using TREF increments,characterized in that every fraction that has an ATREF elutiontemperature between 40° C. and less than about 76° C., has a meltenthalpy (heat of fusion) as measured by DSC, corresponding to theequation:Heat of fusion (J/gm)≦(1.1312)(ATREF elution temperature inCelsius)+22.97.

ATREF Peak Comonomer Composition Measurement by Infra-Red Detector

The comonomer composition of the TREF peak can be measured using an IR4infra-red detector available from Polymer Char, Valencia, Spain(http://www.polymerchar.com/).

The “composition mode” of the detector is equipped with a measurementsensor (CH₂) and composition sensor (CH₃) that are fixed narrow bandinfra-red filters in the region of 2800-3000 cm⁻¹. The measurementsensor detects the methylene (CH₂) carbons on the polymer (whichdirectly relates to the polymer concentration in solution) while thecomposition sensor detects the methyl (CH₃) groups of the polymer. Themathematical ratio of the composition signal (CH₃) divided by themeasurement signal (CH₂) is sensitive to the comonomer content of themeasured polymer in solution and its response is calibrated with knownethylene alpha-olefin copolymer standards.

The detector when used with an ATREF instrument provides both aconcentration (CH₂) and composition (CH₃) signal response of the elutedpolymer during the TREF process. A polymer specific calibration can becreated by measuring the area ratio of the CH₃ to CH₂ for polymers withknown comonomer content (preferably measured by NMR). The comonomercontent of an ATREF peak of a polymer can be estimated by applying a thereference calibration of the ratio of the areas for the individual CH₃and CH₂ response (i.e. area ratio CH₃/CH₂ versus comonomer content).

The area of the peaks can be calculated using a full width/half maximum(FWHM) calculation after applying the appropriate baselines to integratethe individual signal responses from the TREF chromatogram. The fullwidth/half maximum calculation is based on the ratio of methyl tomethylene response area [CH₃/CH₂] from the ATREF infra-red detector,wherein the tallest (highest) peak is identified from the base line, andthen the FWHM area is determined. For a distribution measured using anATREF peak, the FWHM area is defined as the area under the curve betweenT1 and T2, where T1 and T2 are points determined, to the left and rightof the ATREF peak, by dividing the peak height by two, and then drawinga line horizontal to the base line, that intersects the left and rightportions of the ATREF curve.

The application of infra-red spectroscopy to measure the comonomercontent of polymers in this ATREF-infra-red method is, in principle,similar to that of GPC/FTIR systems as described in the followingreferences: Markovich, Ronald P.; Hazlitt, Lonnie G.; Smith, Linley;“Development of gel-permeation chromatography-Fourier transform infraredspectroscopy for characterization of ethylene-based polyolefincopolymers”, Polymeric Materials Science and Engineering (1991), 65,98-100; and Deslauriers, P. J.; Rohlfing, D. C.; Shieh, E. T.;“Quantifying short chain branching microstructures in ethylene-1-olefincopolymers using size exclusion chromatography and Fourier transforminfrared spectroscopy (SEC-FTIR)”, Polymer (2002), 43, 59-170, both ofwhich are incorporated by reference herein in their entirety.

In other embodiments, the inventive ethylene/α-olefin interpolymer ischaracterized by an average block index, ABI, which is greater than zeroand up to about 1.0 and a molecular weight distribution, M_(w)/M_(n),greater than about 1.3. The average block index, ABI, is the weightaverage of the block index (“BI”) for each of the polymer fractionsobtained in preparative TREF from 20° C. and 110° C., with an incrementof 5° C.:ABI=Σ(w ₁ BI _(i))

where BI_(i) is the block index for the ith fraction of the inventiveethylene/α-olefin interpolymer obtained in preparative TREF, and w_(i)is the weight percentage of the ith fraction.

For each polymer fraction, BI is defined by one of the two followingequations (both of which give the same BI value):${BI} = {{\frac{{1/T_{X}} - {1/T_{XO}}}{{1/T_{A}} - {1/T_{AB}}}\quad{or}\quad{BI}} = {- \frac{{{Ln}\quad P_{X}} - {{Ln}\quad P_{XO}}}{{{Ln}\quad P_{A}} - {{Ln}\quad P_{AB}}}}}$

where T_(X) is the preparative ATREF elution temperature for the ithfraction (preferably expressed in Kelvin), P_(X) is the ethylene molefraction for the ith fraction, which can be measured by NMR or IR asdescribed above. P_(AB) is the ethylene mole fraction of the wholeethylene/α-olefin interpolymer (before fractionation), which also can bemeasured by NMR or IR. T_(A) and P_(A) are the ATREF elution temperatureand the ethylene mole fraction for pure “hard segments” (which refer tothe crystalline segments of the interpolymer). As a first orderapproximation, the T_(A) and P_(A) values are set to those for highdensity polyethylene homopolymer, if the actual values for the “hardsegments” are not available. For calculations performed herein, T_(A) is372° K., P_(A) is 1.

T_(AB) is the ATREF temperature for a random copolymer of the samecomposition and having an ethylene mole fraction of P_(AB). T_(AB) canbe calculated from the following equation:Ln P _(AB) =α/T _(AB)+β

where α and β are two constants which can be determined by calibrationusing a number of known random ethylene copolymers. It should be notedthat α and β may vary from instrument to instrument. Moreover, one wouldneed to create their own calibration curve with the polymer compositionof interest and also in a similar molecular weight range as thefractions. There is a slight molecular weight effect. If the calibrationcurve is obtained from similar molecular weight ranges, such effectwould be essentially negligible. In some embodiments, random ethylenecopolymers satisfy the following relationship:Ln P=−237.83/T _(ATREF)+0.639

T_(XO) is the ATREF temperature for a random copolymer of the samecomposition and having an ethylene mole fraction of P_(X). T_(XO) can becalculated from LnP_(X)=α/T_(XO)+β. Conversely, P_(XO) is the ethylenemole fraction for a random copolymer of the same composition and havingan ATREF temperature of T_(X), which can be calculated from LnP_(XO)=α/T_(X)+β.

Once the block index (BI) for each preparative TREF fraction isobtained, the weight average block index, ABI, for the whole polymer canbe calculated. In some embodiments, ABI is greater than zero but lessthan about 0.3 or from about 0.1 to about 0.3. In other embodiments, ABIis greater than about 0.3 and up to about 1.0. Preferably, ABI should bein the range of from about 0.4 to about 0.7, from about 0.5 to about0.7, or from about 0.6 to about 0.9. In some embodiments, ABI is in therange of from about 0.3 to about 0.9, from about 0.3 to about 0.8, orfrom about 0.3 to about 0.7, from about 0.3 to about 0.6, from about 0.3to about 0.5, or from about 0.3 to about 0.4. In other embodiments, ABIis in the range of from about 0.4 to about 1.0, from about 0.5 to about1.0, or from about 0.6 to about 1.0, from about 0.7 to about 1.0, fromabout 0.8 to about 1.0, or from about 0.9 to about 1.0.

Another characteristic of the inventive ethylene/α-olefin interpolymeris that the inventive ethylene/α-olefin interpolymer comprises at leastone polymer fraction which can be obtained by preparative TREF, whereinthe fraction has a block index greater than about 0.1 and up to about1.0 and a molecular weight distribution, M_(w)/M_(n), greater than about1.3. In some embodiments, the polymer fraction has a block index greaterthan about 0.6 and up to about 1.0, greater than about 0.7 and up toabout 1.0, greater than about 0.8 and up to about 1.0, or greater thanabout 0.9 and up to about 1.0. In other embodiments, the polymerfraction has a block index greater than about 0.1 and up to about 1.0,greater than about 0.2 and up to about 1.0, greater than about 0.3 andup to about 1.0, greater than about 0.4 and up to about 1.0, or greaterthan about 0.4 and up to about 1.0. In still other embodiments, thepolymer fraction has a block index greater than about 0.1 and up toabout 0.5, greater than about 0.2 and up to about 0.5, greater thanabout 0.3 and up to about 0.5, or greater than about 0.4 and up to about0.5. In yet other embodiments, the polymer fraction has a block indexgreater than about 0.2 and up to about 0.9, greater than about 0.3 andup to about 0.8, greater than about 0.4 and up to about 0.7, or greaterthan about 0.5 and up to about 0.6.

For copolymers of ethylene and an α-olefin, the inventive polymerspreferably possess (1) a PDI of at least 1.3, more preferably at least1.5, at least 1.7, or at least 2.0, and most preferably at least 2.6, upto a maximum value of 5.0, more preferably up to a maximum of 3.5, andespecially up to a maximum of 2.7; (2) a heat of fusion of 80 J/g orless; (3) an ethylene content of at least 50 weight percent; (4) a glasstransition temperature, T_(g), of less than −25° C., more preferablyless than −30° C., and/or (5) one and only one T_(m).

Further, the inventive polymers can have, alone or in combination withany other properties disclosed herein, a storage modulus, G′, such thatlog(G′) is greater than or equal to 400 kPa, preferably greater than orequal to 1.0 MPa, at a temperature of 100° C. Moreover, the inventivepolymers possess a relatively flat storage modulus as a function oftemperature in the range from 0 to 100° C. (illustrated in FIG. 6) thatis characteristic of block copolymers, and heretofore unknown for anolefin copolymer, especially a copolymer of ethylene and one or moreC₃₋₈ aliphatic α-olefins. (By the term “relatively flat” in this contextis meant that log G′ (in Pascals) decreases by less than one order ofmagnitude between 50 and 100° C., preferably between 0 and 100° C.).

The inventive interpolymers may be further characterized by athermomechanical analysis penetration depth of 1 mm at a temperature ofat least 90° C. as well as a flexural modulus of from 3 kpsi (20 MPa) to13 kpsi (90 MPa). Alternatively, the inventive interpolymers can have athermomechanical analysis penetration depth of 1 mm at a temperature ofat least 104° C. as well as a flexural modulus of at least 3 kpsi (20MPa). They may be characterized as having an abrasion resistance (orvolume loss) of less than 90 mm³. FIG. 7 shows the TMA (1 mm) versusflex modulus for the inventive polymers, as compared to other knownpolymers. The inventive polymers have significantly betterflexibility-heat resistance balance than the other polymers.

Additionally, the ethylene/α-olefin interpolymers can have a melt index,I₂, from 0.01 to 2000 g/10 minutes, preferably from 0.01 to 1000 g/10minutes, more preferably from 0.01 to 500 g/10 minutes, and especiallyfrom 0.01 to 100 g/10 minutes. In certain embodiments, theethylene/α-olefin interpolymers have a melt index, I₂, from 0.01 to 10g/10 minutes, from 0.5 to 50 g/10 minutes, from 1 to 30 g/10 minutes,from 1 to 6 g/10 minutes or from 0.3 to 10 g/10 minutes. In certainembodiments, the melt index for the ethylene/α-olefin polymers is 1 g/10minutes, 3 g/10 minutes or 5 g/10 minutes.

The polymers can have molecular weights, M_(w), from 1,000 g/mole to5,000,000 g/mole, preferably from 1000 g/mole to 1,000,000, morepreferably from 10,000 g/mole to 500,000 g/mole, and especially from10,000 g/mole to 300,000 g/mole. The density of the inventive polymerscan be from 0.80 to 0.99 g/cm³ and preferably for ethylene containingpolymers from 0.85 g/cm³ to 0.97 g/cm³. In certain embodiments, thedensity of the ethylene/α-olefin polymers ranges from 0.860 to 0.925g/cm³ or 0.867 to 0.910 g/cm³.

The process of making the polymers has been disclosed in the followingpatent applications: U.S. Provisional Application No. 60/553,906, filedMar. 17, 2004; U.S. Provisional Application No. 60/662,937, filed Mar.17, 2005; U.S. Provisional Application No. 60/662,939, filed Mar. 17,2005; U.S. Provisional Application No. 60/566,2938, filed Mar. 17, 2005;PCT Application No. PCT/US2005/008916, filed Mar. 17, 2005; PCTApplication No. PCT/US2005/008915, filed Mar. 17, 2005; and PCTApplication No. PCT/US2005/008917, filed Mar. 17, 2005, all of which areincorporated by reference herein in their entirety. For example, onesuch method contains contacting ethylene and optionally one or moreaddition polymerizable monomers other than ethylene under additionpolymerization conditions with a catalyst composition containing:

the admixture or reaction product resulting from combining:

(A) a first olefin polymerization catalyst having a high comonomerincorporation index,

(B) a second olefin polymerization catalyst having a comonomerincorporation index less than 90 percent, preferably less than 50percent, most preferably less than 5 percent of the comonomerincorporation index of catalyst (A), and

(C) a chain shuttling agent.

Representative catalysts and chain shuttling agent are as follows.

Catalyst (A1) is[N-(2,6-di(1-methylethyl)phenyl)amido)(2-isopropylphenyl)(α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)]hafniumdimethyl, prepared according to the teachings of WO 03/40195,2003US0204017, U.S. Ser. No. 10/429,024, filed May 2, 2003, and WO04/24740.

Catalyst (A2) is[N-(2,6-di(1-methylethyl)phenyl)amido)(2-methylphenyl)(1,2-phenylene-(6-pyridin-2-diyl)methane)]hafniumdimethyl, prepared according to the teachings of WO 03/40195,2003US0204017, U.S. Ser. No. 10/429,024, filed May 2, 2003, and WO04/24740.

Catalyst (A3) isbis[N,N′″-(2,4,6-tri(methylphenyl)amido)ethylenediamine]hafniumdibenzyl.

Catalyst (A4) isbis((2-oxoyl-3-(dibenzo-1H-pyrrole-1-yl)-5-(methyl)phenyl)-2-phenoxymethyl)cyclohexane-1,2-diylzirconium (IV) dibenzyl, prepared substantially according to theteachings of US-A-2004/0010103.

Catalyst (B1) is1,2-bis-(3,5-di-t-butylphenylene)(1-(N-(1-methylethyl)immino)methyl)(2-oxoyl)zirconium dibenzyl

Catalyst (B2) is1,2-bis-(3,5-di-t-butylphenylene)(1-(N-(2-methylcyclohexyl)-immino)methyl)(2-oxoyl)zirconium dibenzyl

Catalyst (C1) is(t-butylamido)dimethyl(3-N-pyrrolyl-1,2,3,3a,7a-η-inden-1-yl)silanetitaniumdimethyl prepared substantially according to the techniques of U.S. Pat.No. 6,268,444:

Catalyst (C2) is(t-butylamido)di(4-methylphenyl)(2-methyl-1,2,3,3a,7a-η-inden-1-yl)silanetitaniumdimethyl prepared substantially according to the teachings ofUS-A-2003/004286:

Catalyst (C3) is(t-butylamido)di(4-methylphenyl)(2-methyl-1,2,3,3a,8a-η-s-indacen-1-yl)silanetitaniumdimethyl prepared substantially according to the teachings ofUS-A-2003/004286:

Catalyst (D1) is bis(dimethyldisiloxane)(indene-1-yl)zirconiumdichloride available from Sigma-Aldrich:

Shuttling Agents The shuttling agents employed include diethylzinc,di(1-butyl)zinc, di(n-hexyl)zinc, triethylaluminum, trioctylaluminum,triethylgallium, i-butylaluminum bis(dimethyl(t-butyl)siloxane),i-butylaluminum bis(di(trimethylsilyl)amide), n-octylaluminumdi(pyridine-2-methoxide), bis(n-octadecyl)i-butylaluminum,i-butylaluminum bis(di(n-pentyl)amide), n-octylaluminumbis(2,6-di-t-butylphenoxide, n-octylaluminum di(ethyl(1-naphthyl)amide),ethylaluminum bis(t-butyldimethylsiloxide), ethylaluminumdi(bis(trimethylsilyl)amide), ethylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide), n-octylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide), n-octylaluminumbis(dimethyl(t-butyl)siloxide, ethylzinc (2,6-diphenylphenoxide), andethylzinc (t-butoxide).

Preferably, the foregoing process takes the form of a continuoussolution process for forming block copolymers, especially multi-blockcopolymers, preferably linear multi-block copolymers of two or moremonomers, more especially ethylene and a C₃₋₂₀ olefin or cycloolefin,and most especially ethylene and a C₄₋₂₀ α-olefin, using multiplecatalysts that are incapable of interconversion. That is, the catalystsare chemically distinct. Under continuous solution polymerizationconditions, the process is ideally suited for polymerization of mixturesof monomers at high monomer conversions. Under these polymerizationconditions, shuttling from the chain shuttling agent to the catalystbecomes advantaged compared to chain growth, and multi-block copolymers,especially linear multi-block copolymers are formed in high efficiency.

The inventive interpolymers may be differentiated from conventional,random copolymers, physical blends of polymers, and block copolymersprepared via sequential monomer addition, fluxional catalysts, anionicor cationic living polymerization techniques. In particular, compared toa random copolymer of the same monomers and monomer content atequivalent crystallinity or modulus, the inventive interpolymers havebetter (higher) heat resistance as measured by melting point, higher TMApenetration temperature, higher high-temperature tensile strength,and/or higher high-temperature torsion storage modulus as determined bydynamic mechanical analysis. Compared to a random copolymer containingthe same monomers and monomer content, the inventive interpolymers havelower compression set, particularly at elevated temperatures, lowerstress relaxation, higher creep resistance, higher tear strength, higherblocking resistance, faster setup due to higher crystallization(solidification) temperature, higher recovery (particularly at elevatedtemperatures), better abrasion resistance, higher retractive force, andbetter oil and filler acceptance.

The inventive interpolymers also exhibit a unique crystallization andbranching distribution relationship. That is, the inventiveinterpolymers have a relatively large difference between the tallestpeak temperature measured using CRYSTAF and DSC as a function of heat offusion, especially as compared to random copolymers containing the samemonomers and monomer level or physical blends of polymers, such as ablend of a high density polymer and a lower density copolymer, atequivalent overall density. It is believed that this unique feature ofthe inventive interpolymers is due to the unique distribution of thecomonomer in blocks within the polymer backbone. In particular, theinventive interpolymers may contain alternating blocks of differingcomonomer content (including homopolymer blocks). The inventiveinterpolymers may also contain a distribution in number and/or blocksize of polymer blocks of differing density or comonomer content, whichis a Schultz-Flory type of distribution. In addition, the inventiveinterpolymers also have a unique peak melting point and crystallizationtemperature profile that is substantially independent of polymerdensity, modulus, and morphology. In a preferred embodiment, themicrocrystalline order of the polymers demonstrates characteristicspherulites and lamellae that are distinguishable from random or blockcopolymers, even at PDI values that are less than 1.7, or even less than1.5, down to less than 1.3.

Moreover, the inventive interpolymers may be prepared using techniquesto influence the degree or level of blockiness (i.e., the magnitude ofthe block index for a particular fraction or for the entire polymer).That is the amount of comonomer and length of each polymer block orsegment can be altered by controlling the ratio and type of catalystsand shuttling agent as well as the temperature of the polymerization,and other polymerization variables. A surprising benefit of thisphenomenon is the discovery that as the degree of blockiness isincreased, the optical properties, tear strength, and high temperaturerecovery properties of the resulting polymer are improved. Inparticular, haze decreases while clarity, tear strength, and hightemperature recovery properties increase as the average number of blocksin the polymer increases. By selecting shuttling agents and catalystcombinations having the desired chain transferring ability (high ratesof shuttling with low levels of chain termination) other forms ofpolymer termination are effectively suppressed. Accordingly, little ifany β-hydride elimination is observed in the polymerization ofethylene/α-olefin comonomer mixtures according to embodiments of theinvention, and the resulting crystalline blocks are highly, orsubstantially completely, linear, possessing little or no long chainbranching.

Polymers with highly crystalline chain ends can be selectively preparedin accordance with embodiments of the invention. In elastomerapplications, reducing the relative quantity of polymer that terminateswith an amorphous block reduces the intermolecular dilutive effect oncrystalline regions. This result can be obtained by choosing chainshuttling agents and catalysts having an appropriate response tohydrogen or other chain terminating agents. Specifically, if thecatalyst which produces highly crystalline polymer is more susceptibleto chain termination (such as by use of hydrogen) than the catalystresponsible for producing the less crystalline polymer segment (such asthrough higher comonomer incorporation, regio-error, or atacetic polymerformation), then the highly crystalline polymer segments willpreferentially populate the terminal portions of the polymer. Not onlyare the resulting terminated groups crystalline, but upon termination,the highly crystalline polymer forming catalyst site is once againavailable for reinitiation of polymer formation. The initially formedpolymer is therefore another highly crystalline polymer segment.Accordingly, both ends of the resulting multi-block copolymer arepreferentially highly crystalline.

The ethylene α-olefin interpolymers used in the embodiments of theinvention are preferably interpolymers of ethylene with at least oneC₃-C₂₀ α-olefin. Copolymers of ethylene and a C₃-C₂₀ α-olefin areespecially preferred. The interpolymers may further comprise C₄-C₁₈diolefin and/or alkenylbenzene. Suitable unsaturated comonomers usefulfor polymerizing with ethylene include, for example, ethylenicallyunsaturated monomers, conjugated or nonconjugated dienes, polyenes,alkenylbenzenes, etc. Examples of such comonomers include C₃-C₂₀α-olefins such as propylene, isobutylene, 1-butene, 1-hexene, 1-pentene,4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, and thelike. 1-Butene and 1-octene are especially preferred. Other suitablemonomers include styrene, halo- or alkyl-substituted styrenes,vinylbenzocyclobutane, 1,4-hexadiene, 1,7-octadiene, and naphthenics(e.g., cyclopentene, cyclohexene and cyclooctene).

While ethylene/α-olefin interpolymers are preferred polymers, otherethylene/olefin polymers may also be used. Olefins as used herein referto a family of unsaturated hydrocarbon-based compounds with at least onecarbon-carbon double bond. Depending on the selection of catalysts, anyolefin may be used in embodiments of the invention. Preferably, suitableolefins are C₃-C₂₀ aliphatic and aromatic compounds containing vinylicunsaturation, as well as cyclic compounds, such as cyclobutene,cyclopentene, dicyclopentadiene, and norbornene, including but notlimited to, norbornene substituted in the 5 and 6 position with C₁-C₂₀hydrocarbyl or cyclohydrocarbyl groups. Also included are mixtures ofsuch olefins as well as mixtures of such olefins with C₄-C₄₀ diolefincompounds.

Examples of olefin monomers include, but are not limited to propylene,isobutylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene,1-nonene, 1-decene, and 1-dodecene, 1-tetradecene, 1-hexadecene,1-octadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene,4-methyl-1-pentene, 4,6-dimethyl-1-heptene, 4-vinylcyclohexene,vinylcyclohexane, norbornadiene, ethylidene norbornene, cyclopentene,cyclohexene, dicyclopentadiene, cyclooctene, C₄-C₄₀ dienes, includingbut not limited to 1,3-butadiene, 1,3-pentadiene, 1,4-hexadiene,1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, other C₄-C₄₀ α-olefins, andthe like. In certain embodiments, the α-olefin is propylene, 1-butene,1-pentene, 1-hexene, 1-octene or a combination thereof. Although anyhydrocarbon containing a vinyl group potentially may be used inembodiments of the invention, practical issues such as monomeravailability, cost, and the ability to conveniently remove unreactedmonomer from the resulting polymer may become more problematic as themolecular weight of the monomer becomes too high.

The polymerization processes described herein are well suited for theproduction of olefin polymers containing monovinylidene aromaticmonomers including styrene, o-methyl styrene, p-methyl styrene,t-butylstyrene, and the like. In particular, interpolymers containingethylene and styrene can be prepared by following the teachings herein.Optionally, copolymers containing ethylene, styrene and a C₃-C₂₀ alphaolefin, optionally containing a C₄-C₂₀ diene, having improved propertiescan be prepared.

Suitable non-conjugated diene monomers can be a straight chain, branchedchain or cyclic hydrocarbon diene having from 6 to 15 carbon atoms.Examples of suitable non-conjugated dienes include, but are not limitedto, straight chain acyclic dienes, such as 1,4-hexadiene, 1,6-octadiene,1,7-octadiene, 1,9-decadiene, branched chain acyclic dienes, such as5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene;3,7-dimethyl-1,7-octadiene and mixed isomers of dihydromyricene anddihydroocinene, single ring alicyclic dienes, such as1,3-cyclopentadiene; 1,4-cyclohexadiene; 1,5-cyclooctadiene and1,5-cyclododecadiene, and multi-ring alicyclic fused and bridged ringdienes, such as tetrahydroindene, methyl tetrahydroindene,dicyclopentadiene, bicyclo-(2,2,1)-hepta-2,5-diene; alkenyl, alkylidene,cycloalkenyl and cycloalkylidene norbornenes, such as5-methylene-2-norbornene (MNB); 5-propenyl-2-norbornene,5-isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene,5-cyclohexylidene-2-norbornene, 5-vinyl-2-norbornene, and norbornadiene.Of the dienes typically used to prepare EPDMs, the particularlypreferred dienes are 1,4-hexadiene (HD), 5-ethylidene-2-norbornene(ENB), 5-vinylidene-2-norbornene (VNB), 5-methylene-2-norbornene (MNB),and dicyclopentadiene (DCPD). The especially preferred dienes are5-ethylidene-2-norbornene (ENB) and 1,4-hexadiene (HD).

One class of desirable polymers that can be made in accordance withembodiments of the invention are elastomeric interpolymers of ethylene,a C₃-C₂₀ α-olefin, especially propylene, and optionally one or morediene monomers. Preferred α-olefins for use in this embodiment of theinvention are designated by the formula CH₂═CHR*, where R* is a linearor branched alkyl group of from 1 to 12 carbon atoms. Examples ofsuitable α-olefins include, but are not limited to, propylene,isobutylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and1-octene. A particularly preferred α-olefin is propylene. The propylenebased polymers are generally referred to in the art as EP or EPDMpolymers. Suitable dienes for use in preparing such polymers, especiallymulti-block EPDM type polymers include conjugated or non-conjugated,straight or branched chain-, cyclic- or polycyclic-dienes containingfrom 4 to 20 carbons. Preferred dienes include 1,4-pentadiene,1,4-hexadiene, 5-ethylidene-2-norbornene, dicyclopentadiene,cyclohexadiene, and 5-butylidene-2-norbornene. A particularly preferreddiene is 5-ethylidene-2-norbornene.

Because the diene containing polymers contain alternating segments orblocks containing greater or lesser quantities of the diene (includingnone) and α-olefin (including none), the total quantity of diene andα-olefin may be reduced without loss of subsequent polymer properties.That is, because the diene and α-olefin monomers are preferentiallyincorporated into one type of block of the polymer rather than uniformlyor randomly throughout the polymer, they are more efficiently utilizedand subsequently the crosslink density of the polymer can be bettercontrolled. Such crosslinkable elastomers and the cured products haveadvantaged properties, including higher tensile strength and betterelastic recovery.

In some embodiments, the inventive interpolymers made with two catalystsincorporating differing quantities of comonomer have a weight ratio ofblocks formed thereby from 95:5 to 5:95. The elastomeric polymersdesirably have an ethylene content of from 20 to 90 percent, a dienecontent of from 0.1 to 10 percent, and an α-olefin content of from 10 to80 percent, based on the total weight of the polymer. Furtherpreferably, the multi-block elastomeric polymers have an ethylenecontent of from 60 to 90 percent, a diene content of from 0.1 to 10percent, and an α-olefin content of from 10 to 40 percent, based on thetotal weight of the polymer. Preferred polymers are high molecularweight polymers, having a weight average molecular weight (Mw) from10,000 to about 2,500,000, preferably from 20,000 to 500,000, morepreferably from 20,000 to 350,000, and a polydispersity less than 3.5,more preferably less than 3.0, and a Mooney viscosity (ML (1+4) 125° C.)from 1 to 250. More preferably, such polymers have an ethylene contentfrom 65 to 75 percent, a diene content from 0 to 6 percent, and anα-olefin content from 20 to 35 percent.

The ethylene/α-olefin interpolymers can be functionalized byincorporating at least one functional group in its polymer structure.Exemplary functional groups may include, for example, ethylenicallyunsaturated mono- and di-functional carboxylic acids, ethylenicallyunsaturated mono- and di-functional carboxylic acid anhydrides, saltsthereof and esters thereof. Such functional groups may be grafted to anethylene/α-olefin interpolymer, or it may be copolymerized with ethyleneand an optional additional comonomer to form an interpolymer ofethylene, the functional comonomer and optionally other comonomer(s).Means for grafting functional groups onto polyethylene are described forexample in U.S. Pat. Nos. 4,762,890, 4,927,888, and 4,950,541, thedisclosures of these patents are incorporated herein by reference intheir entirety. One particularly useful functional group is malicanhydride.

The amount of the functional group present in the functionalinterpolymer can vary. The functional group can typically be present ina copolymer-type functionalized interpolymer in an amount of at leastabout 1.0 weight percent, preferably at least about 5 weight percent,and more preferably at least about 7 weight percent. The functionalgroup will typically be present in a copolymer-type functionalizedinterpolymer in an amount less than about 40 weight percent, preferablyless than about 30 weight percent, and more preferably less than about25 weight percent.

More on Block Index

Random copolymers satisfy the following relationship. See P. J. Flory,Trans. Faraday Soc., 51, 848 (1955), which is incorporated by referenceherein in its entirety. $\begin{matrix}{{\frac{1}{T_{m}} - \frac{1}{T_{m}^{0}}} = {{- \left( \frac{R}{\Delta\quad H_{u}} \right)}\ln\quad P}} & (1)\end{matrix}$

In Equation 1, the mole fraction of crystallizable monomers, P, isrelated to the melting temperature, T_(m), of the copolymer and themelting temperature of the pure crystallizable homopolymer, T_(m) ⁰. Theequation is similar to the relationship for the natural logarithm of themole fraction of ethylene as a function of the reciprocal of the ATREFelution temperature (° K.) as shown in FIG. 8 for various homogeneouslybranched copolymers of ethylene and olefins.

As illustrated in FIG. 8, the relationship of ethylene mole fraction toATREF peak elution temperature and DSC melting temperature for varioushomogeneously branched copolymers is analogous to Flory's equation.Similarly, preparative TREF fractions of nearly all random copolymersand random copolymer blends likewise fall on this line, except for smallmolecular weight effects.

According to Flory, if P, the mole fraction of ethylene, is equal to theconditional probability that one ethylene unit will precede or followanother ethylene unit, then the polymer is random. On the other hand ifthe conditional probability that any 2 ethylene units occur sequentiallyis greater than P, then the copolymer is a block copolymer. Theremaining case where the conditional probability is less than P yieldsalternating copolymers.

The mole fraction of ethylene in random copolymers primarily determinesa specific distribution of ethylene segments whose crystallizationbehavior in turn is governed by the minimum equilibrium crystalthickness at a given temperature. Therefore, the copolymer melting andTREF crystallization temperatures of the inventive block copolymers arerelated to the magnitude of the deviation from the random relationshipin FIG. 8, and such deviation is a useful way to quantify how “blocky” agiven TREF fraction is relative to its random equivalent copolymer (orrandom equivalent TREF fraction). The term “blocky” refers to the extenta particular polymer fraction or polymer comprises blocks of polymerizedmonomers or comonomers. There are two random equivalents, onecorresponding to constant temperature and one corresponding to constantmole fraction of ethylene. These form the sides of a right triangle asshown in FIG. 9, which illustrates the definition of the block index.

In FIG. 9, the point (T_(X), P_(X)) represents a preparative TREFfraction, where the ATREF elution temperature, T_(X), and the NMRethylene mole fraction, P_(X), are measured values. The ethylene molefraction of the whole polymer, P_(AB), is also measured by NMR. The“hard segment” elution temperature and mole fraction, (T_(A), P_(A)),can be estimated or else set to that of ethylene homopolymer forethylene copolymers. The T_(AB) value corresponds to the calculatedrandom copolymer equivalent ATREF elution temperature based on themeasured P_(AB). From the measured ATREF elution temperature, T_(X), thecorresponding random ethylene mole fraction, P_(X0), can also becalculated. The square of the block index is defined to be the ratio ofthe area of the (P_(X), T_(X)) triangle and the (T_(A), P_(AB))triangle. Since the right triangles are similar, the ratio of areas isalso the squared ratio of the distances from (T_(A), P_(AB)) and (T_(X),P_(X)) to the random line. In addition, the similarity of the righttriangles means the ratio of the lengths of either of the correspondingsides can be used instead of the areas.${BI} = {{\frac{{1/T_{X}} - {1/T_{XO}}}{{1/T_{A}} - {1/T_{AB}}}\quad{or}\quad{BI}} = {- \frac{{{Ln}\quad P_{X}} - {{Ln}\quad P_{XO}}}{{{Ln}\quad P_{A}} - {{Ln}\quad P_{AB}}}}}$

It should be noted that the most perfect block distribution wouldcorrespond to a whole polymer with a single eluting fraction at thepoint (T_(A), P_(AB)), because such a polymer would preserve theethylene segment distribution in the “hard segment”, yet contain all theavailable octene (presumably in runs that are nearly identical to thoseproduced by the soft segment catalyst). In most cases, the “softsegment” will not crystallize in the ATREF (or preparative TREF).

The following examples are provided to illustrate the synthesis of theinventive ethylene/α-olefin interpolymers. Certain comparisons are madewith some existing polymers.

Testing Methods

In the examples that follow, the following analytical techniques areemployed:

GPC Method for Samples 14 and A-C

An automated liquid-handling robot equipped with a heated needle set to160° C. is used to add enough 1,2,4-trichlorobenzene stabilized with 300ppm Ionol to each dried polymer sample to give a final concentration of30 mg/mL. A small glass stir rod is placed into each tube and thesamples are heated to 160° C. for 2 hours on a heated, orbital-shakerrotating at 250 rpm. The concentrated polymer solution is then dilutedto 1 mg/ml using the automated liquid-handling robot and the heatedneedle set to 160° C.

A Symyx Rapid GPC system is used to determine the molecular weight datafor each sample. A Gilson 350 pump set at 2.0 ml/min flow rate is usedto pump helium-purged 1,2-dichlorobenzene stabilized with 300 ppm Ionolas the mobile phase through three Plgel 10 micrometer (μm) Mixed B 300mm×7.5 mm columns placed in series and heated to 160° C. A Polymer LabsELS1000 Detector is used with the Evaporator set to 250° C., theNebulizer set to 165° C., and the nitrogen flow rate set to 1.8 SLM at apressure of 60-80 psi (400-600 kPa) N₂. The polymer samples are heatedto 160° C. and each sample injected into a 250 μl loop using theliquid-handling robot and a heated needle. Serial analysis of thepolymer samples using two switched loops and overlapping injections areused. The sample data is collected and analyzed using Symyx Epoch™software. Peaks are manually integrated and the molecular weightinformation reported uncorrected against a polystyrene standardcalibration curve.

Standard CRYSTAF Method

Branching distributions are determined by crystallization analysisfractionation (CRYSTAF) using a CRYSTAF 200 unit commercially availablefrom PolymerChar, Valencia, Spain. The samples are dissolved in 1,2,4trichlorobenzene at 160° C. (0.66 mg/mL) for 1 hr and stabilized at 95°C. for 45 minutes. The sampling temperatures range from 95 to 30° C. ata cooling rate of 0.2° C./min. An infrared detector is used to measurethe polymer solution concentrations. The cumulative solubleconcentration is measured as the polymer crystallizes while thetemperature is decreased. The analytical derivative of the cumulativeprofile reflects the short chain branching distribution of the polymer.

The CRYSTAF peak temperature and area are identified by the peakanalysis module included in the CRYSTAF Software (Version 2001.b,PolymerChar, Valencia, Spain). The CRYSTAF peak finding routineidentifies a peak temperature as a maximum in the dW/dT curve and thearea between the largest positive inflections on either side of theidentified peak in the derivative curve. To calculate the CRYSTAF curve,the preferred processing parameters are with a temperature limit of 70°C. and with smoothing parameters above the temperature limit of 0.1, andbelow the temperature limit of 0.3.

DSC Standard Method (Excluding Samples 1-4 and A-C)

Differential Scanning Calorimetry results are determined using a TAImodel Q1000 DSC equipped with an RCS cooling accessory and anautosampler. A nitrogen purge gas flow of 50 ml/min is used. The sampleis pressed into a thin film and melted in the press at about 175° C. andthen air-cooled to room temperature (25° C.). 3-10 mg of material isthen cut into a 6 mm diameter disk, accurately weighed, placed in alight aluminum pan (ca 50 mg), and then crimped shut. The thermalbehavior of the sample is investigated with the following temperatureprofile. The sample is rapidly heated to 180° C. and held isothermal for3 minutes in order to remove any previous thermal history. The sample isthen cooled to −40° C. at 10° C./min cooling rate and held at −40° C.for 3 minutes. The sample is then heated to 150° C. at 10° C./minheating rate. The cooling and second heating curves are recorded.

The DSC melting peak is measured as the maximum in heat flow rate (W/g)with respect to the linear baseline drawn between −30° C. and the end ofmelting. The heat of fusion is measured as the area under the meltingcurve between −30° C. and the end of melting using a linear baseline.

GPC Method (Excluding Samples 14 and A-C)

The gel permeation chromatographic system consists of either a PolymerLaboratories Model PL-210 or a Polymer Laboratories Model PL-220instrument. The column and carousel compartments are operated at 140° C.Three Polymer Laboratories 10-micron Mixed-B columns are used. Thesolvent is 1,2,4 trichlorobenzene. The samples are prepared at aconcentration of 0.1 grams of polymer in 50 milliliters of solventcontaining 200 ppm of butylated hydroxytoluene (BHT). Samples areprepared by agitating lightly for 2 hours at 160° C. The injectionvolume used is 100 microliters and the flow rate is 1.0 ml/minute.

Calibration of the GPC column set is performed with 21 narrow molecularweight distribution polystyrene standards with molecular weights rangingfrom 580 to 8,400,000, arranged in 6 “cocktail” mixtures with at least adecade of separation between individual molecular weights. The standardsare purchased from Polymer Laboratories (Shropshire, UK). Thepolystyrene standards are prepared at 0.025 grams in 50 milliliters ofsolvent for molecular weights equal to or greater than 1,000,000, and0.05 grams in 50 milliliters of solvent for molecular weights less than1,000,000. The polystyrene standards are dissolved at 80° C. with gentleagitation for 30 minutes. The narrow standards mixtures are run firstand in order of decreasing highest molecular weight component tominimize degradation. The polystyrene standard peak molecular weightsare converted to polyethylene molecular weights using the followingequation (as described in Williams and Ward, J. Polym. Sci., Polym.Let., 6, 621 (1968)): M_(polyethylene)=0.431(M_(polystyrene)).

Polyethylene equivalent molecular weight calculations are performedusing Viscotek TriSEC software Version 3.0.

Compression Set

Compression set is measured according to ASTM D 395. The sample isprepared by stacking 25.4 mm diameter round discs of 3.2 mm, 2.0 mm, and0.25 mm thickness until a total thickness of 12.7 mm is reached. Thediscs are cut from 12.7 cm×12.7 cm compression molded plaques moldedwith a hot press under the following conditions: zero pressure for 3 minat 190° C., followed by 86 MPa for 2 min at 190° C., followed by coolinginside the press with cold running water at 86 MPa.

Density

Samples for density measurement are prepared according to ASTM D 1928.

Measurements are made within one hour of sample pressing using ASTMD792, Method B.

Flexural/Secant Modulus/Storage Modulus

Samples are compression molded using ASTM D 1928. Flexural and 2 percentsecant moduli are measured according to ASTM D-790. Storage modulus ismeasured according to ASTM D 5026-01 or equivalent technique.

Optical Properties

Films of 0.4 mm thickness are compression molded using a hot press(Carver Model #4095-4PR1001R). The pellets are placed betweenpolytetrafluoroethylene sheets, heated at 190° C. at 55 psi (380 kPa)for 3 min, followed by 1.3 MPa for 3 min, and then 2.6 MPa for 3 min.The film is then cooled in the press with running cold water at 1.3 MPafor 1 min. The compression molded films are used for opticalmeasurements, tensile behavior, recovery, and stress relaxation.

Clarity is measured using BYK Gardner Haze-gard as specified in ASTM D1746.

45° gloss is measured using BYK Gardner Glossmeter Microgloss 45° asspecified in ASTM D-2457

Internal haze is measured using BYK Gardner Haze-gard based on ASTM D1003 Procedure A. Mineral oil is applied to the film surface to removesurface scratches.

Mechanical Properties—Tensile, Hysteresis, and Tear

Stress-strain behavior in uniaxial tension is measured using ASTM D 1708microtensile specimens. Samples are stretched with an Instron at 500%min⁻¹ at 21° C. Tensile strength and elongation at break are reportedfrom an average of 5 specimens.

100% and 300% Hysteresis is determined from cyclic loading to 100% and300% strains using ASTM D 1708 microtensile specimens with an Instron™instrument. The sample is loaded and unloaded at 267% min⁻¹ for 3 cyclesat 21° C. Cyclic experiments at 300% and 80° C. are conducted using anenvironmental chamber. In the 80° C. experiment, the sample is allowedto equilibrate for 45 minutes at the test temperature before testing. Inthe 21° C., 300% strain cyclic experiment, the retractive stress at 150%strain from the first unloading cycle is recorded. Percent recovery forall experiments are calculated from the first unloading cycle using thestrain at which the load returned to the base line. The percent recoveryis defined as:${\%\quad{Recovery}} = {\frac{ɛ_{f} - ɛ_{s}}{ɛ_{f}} \times 100}$

where ε_(f) is the strain taken for cyclic loading and ε_(s) is thestrain where the load returns to the baseline during the 1^(st)unloading cycle.

Stress relaxation is measured at 50 percent strain and 37° C. for 12hours using an Instron™ instrument equipped with an environmentalchamber. The gauge geometry was 76 mm×25 mm×0.4 mm. After equilibratingat 37° C. for 45 min in the environmental chamber, the sample wasstretched to 50% strain at 333% min⁻¹. Stress was recorded as a functionof time for 12 hours. The percent stress relaxation after 12 hours wascalculated using the formula:${\%\quad{Stress}\quad{Relaxation}} = {\frac{L_{0} - L_{12}}{L_{0}} \times 100}$

where L₀ is the load at 50% strain at 0 time and L₁₂ is the load at 50percent strain after 12 hours.

Tensile notched tear experiments are carried out on samples having adensity of 0.88 g/cc or less using an Instron™ instrument. The geometryconsists of a gauge section of 76 mm×13 mm×0.4 mm with a 2 mm notch cutinto the sample at half the specimen length. The sample is stretched at508 mm min⁻¹ at 21° C. until it breaks. The tear energy is calculated asthe area under the stress-elongation curve up to strain at maximum load.An average of at least 3 specimens are reported.

TMA

Thermal Mechanical Analysis (Penetration Temperature) is conducted on 30mm diameter×3.3 mm thick, compression molded discs, formed at 180° C.and 10 MPa molding pressure for 5 minutes and then air quenched. Theinstrument used is a TMA 7, brand available from Perkin-Elmer. In thetest, a probe with 1.5 mm radius tip (P/N N519-0416) is applied to thesurface of the sample disc with IN force. The temperature is raised at5° C./min from 25° C. The probe penetration distance is measured as afunction of temperature. The experiment ends when the probe haspenetrated 1 mm into the sample.

DMA

Dynamic Mechanical Analysis (DMA) is measured on compression moldeddisks formed in a hot press at 180° C. at 10 MPa pressure for 5 minutesand then water cooled in the press at 90° C./min. Testing is conductedusing an ARES controlled strain rheometer (TA instruments) equipped withdual cantilever fixtures for torsion testing.

A 1.5 mm plaque is pressed and cut in a bar of dimensions 32×12 mm. Thesample is clamped at both ends between fixtures separated by 10 mm (gripseparation ΔL) and subjected to successive temperature steps from −100°C. to 200° C. (5° C. per step). At each temperature the torsion modulusG′ is measured at an angular frequency of 10 rad/s, the strain amplitudebeing maintained between 0.1 percent and 4 percent to ensure that thetorque is sufficient and that the measurement remains in the linearregime.

An initial static force of 10 g is maintained (auto-tension mode) toprevent slack in the sample when thermal expansion occurs. As aconsequence, the grip separation ΔL increases with the temperature,particularly above the melting or softening point of the polymer sample.The test stops at the maximum temperature or when the gap between thefixtures reaches 65 mm.

Melt Index

Melt index, or I₂, is measured in accordance with ASTM D 1238, Condition190° C./2.16 kg. Melt index, or I₁₀ is also measured in accordance withASTM D 1238, Condition 190° C./10 kg.

ATREF

Analytical temperature rising elution fractionation (ATREF) analysis isconducted according to the method described in U.S. Pat. No. 4,798,081and Wilde, L.; Ryle, T. R.; Knobeloch, D. C.; Peat, I. R.; Determinationof Branching Distributions in Polyethylene and Ethylene Copolymers, J.Polym. Sci., 20, 441-455 (1982), which are incorporated by referenceherein in their entirety. The composition to be analyzed is dissolved intrichlorobenzene and allowed to crystallize in a column containing aninert support (stainless steel shot) by slowly reducing the temperatureto 20° C. at a cooling rate of 0.1° C./min. The column is equipped withan infrared detector. An ATREF chromatogram curve is then generated byeluting the crystallized polymer sample from the column by slowlyincreasing the temperature of the eluting solvent (trichlorobenzene)from 20 to 120° C. at a rate of 1.5° C./min.

¹³C NMR Analysis

The samples are prepared by adding approximately 3 g of a 50/50 mixtureof tetrachloroethane-d²/orthodichlorobenzene to 0.4 g sample in a 10 mmNMR tube. The samples are dissolved and homogenized by heating the tubeand its contents to 150° C. The data are collected using a JEOL Eclipse™400 MHz spectrometer or a Varian Unity Plus™ 400 MHz spectrometer,corresponding to a ¹³C resonance frequency of 100.5 MHz. The data areacquired using 4000 transients per data file with a 6 second pulserepetition delay. To achieve minimum signal-to-noise for quantitativeanalysis, multiple data files are added together. The spectral width is25,000 Hz with a minimum file size of 32 K data points. The samples areanalyzed at 130° C. in a 10 mm broad band probe. The comonomerincorporation is determined using Randall's triad method (Randall, J.C.; JMS-Rev. Macromol. Chem. Phys., C29, 201-317 (1989), which isincorporated by reference herein in its entirety.

Polymer Fractionation by TREF

Large-scale TREF fractionation is carried by dissolving 15-20 g ofpolymer in 2 liters of 1,2,4-trichlorobenzene (TCB)by stirring for 4hours at 160° C. The polymer solution is forced by 15 psig (100 kPa)nitrogen onto a 3 inch by 4 foot (7.6 cm×12 cm) steel column packed witha 60:40 (v:v). mix of 30-40 mesh (600-425 μm) spherical, technicalquality glass beads (available from Potters Industries, HC 30 Box 20,Brownwood, Tex., 76801) and stainless steel, 0.028″ (0.7 mm) diametercut wire shot (available from Pellets, Inc. 63 Industrial Drive, NorthTonawanda, N.Y., 14120). The column is immersed in a thermallycontrolled oil jacket, set initially to 160° C. The column is firstcooled ballistically to 125° C., then slow cooled to 20° C. at 0.04° C.per minute and held for one hour. Fresh TCB is introduced at about 65ml/min while the temperature is increased at 0.167° C. per minute.

Approximately 2000 ml portions of eluant from the preparative TREFcolumn are collected in a 16 station, heated fraction collector. Thepolymer is concentrated in each fraction using a rotary evaporator untilabout 50 to 100 ml of the polymer solution remains. The concentratedsolutions are allowed to stand overnight before adding excess methanol,filtering, and rinsing (approx. 300-500 ml of methanol including thefinal rinse). The filtration step is performed on a 3 position vacuumassisted filtering station using 5.0 μm polytetrafluoroethylene coatedfilter paper (available from Osmonics Inc., Cat# Z50WP04750). Thefiltrated fractions are dried overnight in a vacuum oven at 60° C. andweighed on an analytical balance before further testing.

Catalysts

The term “overnight”, if used, refers to a time of approximately 16-18hours, the term “room temperature”, refers to a temperature of 20-25°C., and the term “mixed alkanes” refers to a commercially obtainedmixture of C₆₋₉ aliphatic hydrocarbons available under the tradedesignation Isopar E®, from ExxonMobil Chemical Company. In the eventthe name of a compound herein does not conform to the structuralrepresentation thereof, the structural representation shall control. Thesynthesis of all metal complexes and the preparation of all screeningexperiments were carried out in a dry nitrogen atmosphere using dry boxtechniques. All solvents used were HPLC grade and were dried beforetheir use.

MMAO refers to modified methylalumoxane, a triisobutylaluminum modifiedmethylalumoxane available commercially from Akzo-Noble Corporation.

The preparation of catalyst (B1) is conducted as follows.

a) Preparation of(1-methylethyl)(2-hydroxy-3,5-di(t-butyl)phenyl)methylimine

3,5-Di-t-butylsalicylaldehyde (3.00 g) is added to 10 mL ofisopropylamine. The solution rapidly turns bright yellow. After stirringat ambient temperature for 3 hours, volatiles are removed under vacuumto yield a bright yellow, crystalline solid (97 percent yield).

b) Preparation of1,2-bis-(3,5-di-t-butylphenylene)(1-(N-(1-methylethyl)immino)methyl)(2-oxoyl)zirconium dibenzyl

A solution of (1-methylethyl)(2-hydroxy-3,5-di(t-butyl)phenyl)imine (605mg, 2.2 mmol) in 5 mL toluene is slowly added to a solution ofZr(CH₂Ph)₄ (500 mg, 1.1 mmol) in 50 mL toluene. The resulting darkyellow solution is stirred for 30 min. Solvent is removed under reducedpressure to yield the desired product as a reddish-brown solid.

The preparation of catalyst (B2) is conducted as follows.

a) Preparation of(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)imine

2-Methylcyclohexylamine (8.44 mL, 64.0 mmol) is dissolved in methanol(90 mL), and di-t-butylsalicaldehyde (10.00 g, 42.67 mmol) is added. Thereaction mixture is stirred for three hours and then cooled to −25° C.for 12 hrs. The resulting yellow solid precipitate is collected byfiltration and washed with cold methanol (2×15 mL), and then dried underreduced pressure. The yield is 11.17 g of a yellow solid. ¹H NMR isconsistent with the desired product as a mixture of isomers.

b) Preparation ofbis-(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)immino)zirconium dibenzyl

A solution of(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)imine (7.63g, 23.2 mmol) in 200 mL toluene is slowly added to a solution ofZr(CH₂Ph)₄ (5.28 g, 11.6 mmol) in 600 mL toluene. The resulting darkyellow solution is stirred for 1 hour at 25° C. The solution is dilutedfurther with 680 mL toluene to give a solution having a concentration of0.00783 M.

Cocatalyst 1 A mixture of methyldi(C₁₄₋₁₈ alkyl)ammonium salts oftetrakis(pentafluorophenyl)borate (here-in-after armeenium borate),prepared by reaction of a long chain trialkylamine (Armeen™ M2HT,available from Akzo-Nobel, Inc.), HCl and Li[B(C₆F₅)₄], substantially asdisclosed in U.S. Pat. No. 5,919,9883, Ex. 2.

Cocatalyst 2 Mixed C₁₄₋₁₈ alkyldimethylammonium salt ofbis(tris(pentafluorophenyl)-alumane)-2-undecylimidazolide, preparedaccording to U.S. Pat. No. 6,395,671, Ex. 16.

Shuttling Agents The shuttling agents employed include diethylzinc (DEZ,SA1), di(1-butyl)zinc (SA2), di(n-hexyl)zinc (SA3), triethylaluminum(TEA, SA4), trioctylaluminum (SA5), triethylgallium (SA6),i-butylaluminum bis(dimethyl(t-butyl)siloxane) (SA7), i-butylaluminumbis(di(trimethylsilyl)amide) (SA8), n-octylaluminumdi(pyridine-2-methoxide) (SA9), bis(n-octadecyl)i-butylaluminum (SA10),i-butylaluminum bis(di(n-pentyl)amide) (SA11), n-octylaluminumbis(2,6-di-t-butylphenoxide) (SA12), n-octylaluminumdi(ethyl(1-naphthyl)amide) (SA 13), ethylaluminumbis(t-butyldimethylsiloxide) (SA 14), ethylaluminumdi(bis(trimethylsilyl)amide) (SA 15), ethylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide) (SA 16), n-octylaluminumbis(2,3,6,7-dibenzo-1-azacycloheptaneamide) (SA 17), n-octylaluminumbis(dimethyl(t-butyl)siloxide(SA 18), ethylzinc (2,6-diphenylphenoxide)(SA 19), and ethylzinc (t-butoxide) (SA20).

EXAMPLES 1-4, COMPARATIVE A-C

General High Throughput Parallel Polymerization Conditions

Polymerizations are conducted using a high throughput, parallelpolymerization reactor (PPR) available from Symyx Technologies, Inc. andoperated substantially according to U.S. Pat. Nos. 6,248,540, 6,030,917,6,362,309, 6,306,658, and 6,316,663. Ethylene copolymerizations areconducted at 130° C. and 200 psi (1.4 MPa) with ethylene on demand using1.2 equivalents of cocatalyst 1 based on total catalyst used (1.1equivalents when MMAO is present). A series of polymerizations areconducted in a parallel pressure reactor (PPR) containing 48 individualreactor cells in a 6×8 array that are fitted with a pre-weighed glasstube. The working volume in each reactor cell is 6000 μL. Each cell istemperature and pressure controlled with stirring provided by individualstirring paddles. The monomer gas and quench gas are plumbed directlyinto the PPR unit and controlled by automatic valves. Liquid reagentsare robotically added to each reactor cell by syringes and the reservoirsolvent is mixed alkanes. The order of addition is mixed alkanes solvent(4 ml), ethylene, 1-octene comonomer (1 ml), cocatalyst 1 or cocatalyst1/MMAO mixture, shuttling agent, and catalyst or catalyst mixture. Whena mixture of cocatalyst 1 and MMAO or a mixture of two catalysts isused, the reagents are premixed in a small vial immediately prior toaddition to the reactor. When a reagent is omitted in an experiment, theabove order of addition is otherwise maintained. Polymerizations areconducted for approximately 1-2 minutes, until predetermined ethyleneconsumptions are reached. After quenching with CO, the reactors arecooled and the glass tubes are unloaded. The tubes are transferred to acentrifuge/vacuum drying unit, and dried for 12 hours at 60° C. Thetubes containing dried polymer are weighed and the difference betweenthis weight and the tare weight gives the net yield of polymer. Resultsare contained in Table 1. In Table 1 and elsewhere in the application,comparative compounds are indicated by an asterisk (*).

Examples 1-4 demonstrate the synthesis of linear block copolymers inaccording with some embodiments of the invention as evidenced by theformation of a very narrow MWD, essentially monomodal copolymer when DEZis present and a bimodal, broad molecular weight distribution product (amixture of separately produced polymers) in the absence of DEZ. Due tothe fact that Catalyst (A1) is known to incorporate more octene thanCatalyst (B1), the different blocks or segments of the resultingcopolymers of the invention are distinguishable based on branching ordensity. TABLE 1 Cat. (A1) Cat (B1) Cocat MMAO shuttling Ex. (μmol)(μmol) (μmol) (μmol) agent (μmol) Yield (g) Mn Mw/Mn hexyls¹ A* 0.06 —0.066 0.3 — 0.1363 300502 3.32 — B* — 0.1 0.110 0.5 — 0.1581 36957 1.222.5 C* 0.06 0.1 0.176 0.8 — 0.2038 45526 5.30² 5.5 1 0.06 0.1 0.192 —DEZ (8.0) 0.1974 28715 1.19 4.8 2 0.06 0.1 0.192 — DEZ (80.0) 0.14682161 1.12 14.4 3 0.06 0.1 0.192 — TEA (8.0) 0.208 22675 1.71 4.6 4 0.060.1 0.192 — TEA (80.0) 0.1879 3338 1.54 9.4¹C₆ or higher chain content per 1000 carbons²Bimodal molecular weight distribution

It may be seen the polymers produced according to certain embodiments ofthe invention have a relatively narrow polydispersity (Mw/Mn) and largerblock-copolymer content (trimer, tetramer, or larger) than polymersprepared in the absence of the shuttling agent.

Further characterizing data for the polymers of Table 1 are determinedby reference to the figures. More specifically DSC and ATREF resultsshow the following:

The DSC curve for the polymer of Example 1 shows a 115.7° C. meltingpoint (Tm) with a heat of fusion of 158.1 J/g. The corresponding CRYSTAFcurve shows the tallest peak at 34.5° C. with a peak area of 52.9percent. The difference between the DSC Tm and the Tcrystaf is 81.2° C.

The DSC curve for the polymer of Example 2 shows a peak with a 109.7° C.melting point (Tm) with a heat of fusion of 214.0 J/g. The correspondingCRYSTAF curve shows the tallest peak at 46.2° C. with a peak area of57.0 percent. The difference between the DSC Tm and the Tcrystaf is63.5° C.

The DSC curve for the polymer of Example 3 shows a peak with a 120.7° C.melting point (Tm) with a heat of fusion of 160.1 J/g. The correspondingCRYSTAF curve shows the tallest peak at 66.1° C. with a peak area of71.8 percent. The difference between the DSC Tm and the Tcrystaf is54.6° C.

The DSC curve for the polymer of Example 4 shows a peak with a 104.5° C.melting point (Tm) with a heat of fusion of 170.7 J/g. The correspondingCRYSTAF curve shows the tallest peak at 30° C. with a peak area of 18.2percent. The difference between the DSC Tm and the Tcrystaf is 74.5° C.

The DSC curve for comparative A shows a 90.0° C. melting point (Tm) witha heat of fusion of 86.7 J/g. The corresponding CRYSTAF curve shows thetallest peak at 48.5° C. with a peak area of 29.4 percent. Both of thesevalues are consistent with a resin that is low in density. Thedifference between the DSC Tm and the Tcrystaf is 41.8° C.

The DSC curve for Comparative B shows a 129.8° C. melting point (Tm)with a heat of fusion of 237.0 J/g. The corresponding CRYSTAF curveshows the tallest peak at 82.4° C. with a peak area of 83.7 percent.Both of these values are consistent with a resin that is high indensity. The difference between the DSC Tm and the Tcrystaf is 47.4° C.

The DSC curve for Comparative C shows a 125.3° C. melting point (Tm)with a heat of fusion of 143.0 J/g. The corresponding CRYSTAF curveshows the tallest peak at 81.8° C. with a peak area of 34.7 percent aswell as a lower crystalline peak at 52.4° C. The separation between thetwo peaks is consistent with the presence of a high crystalline and alow crystalline polymer. The difference between the DSC Tm and theTcrystaf is 43.5° C.

EXAMPLES 5-19, COMPARATIVES D-F. CONTINUOUS SOLUTION POLYMERIZATIONCATALYST A1/B2+DEZ

Continuous solution polymerizations are carried out in a computercontrolled autoclave reactor equipped with an internal stirrer. Purifiedmixed alkanes solvent (Isopar™ E available from ExxonMobil ChemicalCompany), ethylene at 2.70 lbs/hour (1.22 kg/hour), 1-octene, andhydrogen (where used) are supplied to a 3.8 L reactor equipped with ajacket for temperature control and an internal thermocouple. The solventfeed to the reactor is measured by a mass-flow controller. A variablespeed diaphragm pump controls the solvent flow rate and pressure to thereactor. At the discharge of the pump, a side stream is taken to provideflush flows for the catalyst and cocatalyst 1 injection lines and thereactor agitator. These flows are measured by Micro-Motion mass flowmeters and controlled by control valves or by the manual adjustment ofneedle valves. The remaining solvent is combined with 1-octene,ethylene, and hydrogen (where used) and fed to the reactor. A mass flowcontroller is used to deliver hydrogen to the reactor as needed. Thetemperature of the solvent/monomer solution is controlled by use of aheat exchanger before entering the reactor. This stream enters thebottom of the reactor. The catalyst component solutions are meteredusing pumps and mass flow meters and are combined with the catalystflush solvent and introduced into the bottom of the reactor. The reactoris run liquid-full at 500 psig (3.45 MPa) with vigorous stirring.Product is removed through exit lines at the top of the reactor. Allexit lines from the reactor are steam traced and insulated.Polymerization is stopped by the addition of a small amount of waterinto the exit line along with any stabilizers or other additives andpassing the mixture through a static mixer. The product stream is thenheated by passing through a heat exchanger before devolatilization. Thepolymer product is recovered by extrusion using a devolatilizingextruder and water cooled pelletizer. Process details and results arecontained in Table 2. Selected polymer properties are provided in Table3. TABLE 2 Process details for preparation of exemplary polymers Cat CatA1 Cat B2 DEZ DEZ Cocat Cocat Poly C₈H₁₆ Solv. H₂ T A1² Flow B2³ FlowConc Flow Conc. Flow [C₂H₄]/ Rate⁵ Conv Solids Ex. kg/hr kg/hr sccm¹ °C. ppm kg/hr ppm kg/hr % kg/hr ppm kg/hr [DEZ]⁴ kg/hr %⁶ % Eff.⁷ D* 1.6312.7 29.90 120 142.2 0.14 — — 0.19 0.32 820 0.17 536 1.81 88.8 11.2 95.2E* ″ 9.5 5.00 ″ — — 109 0.10 0.19 ″ 1743 0.40 485 1.47 89.9 11.3 126.8F* ″ 11.3 251.6 ″ 71.7 0.06 30.8 0.06 — — ″ 0.11 — 1.55 88.5 10.3 257.75 ″ ″ — ″ ″ 0.14 30.8 0.13 0.17 0.43 ″ 0.26 419 1.64 89.6 11.1 118.3 6 ″″ 4.92 ″ ″ 0.10 30.4 0.08 0.17 0.32 ″ 0.18 570 1.65 89.3 11.1 172.7 7 ″″ 21.70 ″ ″ 0.07 30.8 0.06 0.17 0.25 ″ 0.13 718 1.60 89.2 10.6 244.1 8 ″″ 36.90 ″ ″ 0.06 ″ ″ ″ 0.10 ″ 0.12 1778 1.62 90.0 10.8 261.1 9 ″ ″ 78.43″ ″ ″ ″ ″ ″ 0.04 ″ ″ 4596 1.63 90.2 10.8 267.9 10 ″ ″ 0.00 123 71.1 0.1230.3 0.14 0.34 0.19 1743 0.08 415 1.67 90.31 11.1 131.1 11 ″ ″ ″ 12071.1 0.16 ″ 0.17 0.80 0.15 1743 0.10 249 1.68 89.56 11.1 100.6 12 ″ ″ ″121 71.1 0.15 ″ 0.07 ″ 0.09 1743 0.07 396 1.70 90.02 11.3 137.0 13 ″ ″ ″122 71.1 0.12 ″ 0.06 ″ 0.05 1743 0.05 653 1.69 89.64 11.2 161.9 14 ″ ″ ″120 71.1 0.05 ″ 0.29 ″ 0.10 1743 0.10 395 1.41 89.42 9.3 114.1 15 2.45 ″″ ″ 71.1 0.14 ″ 0.17 ″ 0.14 1743 0.09 282 1.80 89.33 11.3 121.3 16 ″ ″ ″122 71.1 0.10 ″ 0.13 ″ 0.07 1743 0.07 485 1.78 90.11 11.2 159.7 17 ″ ″ ″121 71.1 0.10 ″ 0.14 ″ 0.08 1743 ″ 506 1.75 89.08 11.0 155.6 18 0.69 ″ ″121 71.1 ″ ″ 0.22 ″ 0.11 1743 0.10 331 1.25 89.93 8.8 90.2 19 0.32 ″ ″122 71.1 0.06 ″ ″ ″ 0.09 1743 0.08 367 1.16 90.74 8.4 106.0*Comparative, not an example of the invention¹standard cm³/min²[N-(2,6-di(1-methylethyl)phenyl)amido)(2-isopropylphenyl)(α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)]hafniumdimethyl³bis-(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)immino)zirconiumdibenzyl⁴molar ratio in reactor⁵polymer production rate⁶percent ethylene conversion in reactor⁷efficiency, kg polymer/g M where g M = g Hf + g Zr

TABLE 3 Properties of exemplary polymers Heat of CRYSTAF Density Mw MnFusion T_(m) T_(c) T_(CRYSTAF) Tm − T_(CRYSTAF) Peak Area Ex. (g/cm³) I₂I₁₀ I₁₀/I₂ (g/mol) (g/mol) Mw/Mn (J/g) (° C.) (° C.) (° C.) (° C.)(percent) D* 0.8627 1.5 10.0 6.5 110,000 55,800 2.0 32 37 45 30 7 99 E*0.9378 7.0 39.0 5.6 65,000 33,300 2.0 183 124 113 79 45 95 F* 0.8895 0.912.5 13.4 137,300 9,980 13.8 90 125 111 78 47 20 5 0.8786 1.5 9.8 6.7104,600 53,200 2.0 55 120 101 48 72 60 6 0.8785 1.1 7.5 6.5 109600 533002.1 55 115 94 44 71 63 7 0.8825 1.0 7.2 7.1 118,500 53,100 2.2 69 121103 49 72 29 8 0.8828 0.9 6.8 7.7 129,000 40,100 3.2 68 124 106 80 43 139 0.8836 1.1 9.7 9.1 129600 28700 4.5 74 125 109 81 44 16 10 0.8784 1.27.5 6.5 113,100 58,200 1.9 54 116 92 41 75 52 11 0.8818 9.1 59.2 6.566,200 36,500 1.8 63 114 93 40 74 25 12 0.8700 2.1 13.2 6.4 101,50055,100 1.8 40 113 80 30 83 91 13 0.8718 0.7 4.4 6.5 132,100 63,600 2.142 114 80 30 81 8 14 0.9116 2.6 15.6 6.0 81,900 43,600 1.9 123 121 10673 48 92 15 0.8719 6.0 41.6 6.9 79,900 40,100 2.0 33 114 91 32 82 10 160.8758 0.5 3.4 7.1 148,500 74,900 2.0 43 117 96 48 69 65 17 0.8757 1.711.3 6.8 107,500 54,000 2.0 43 116 96 43 73 57 18 0.9192 4.1 24.9 6.172,000 37,900 1.9 136 120 106 70 50 94 19 0.9344 3.4 20.3 6.0 76,80039,400 1.9 169 125 112 80 45 88

The resulting polymers are tested by DSC and ATREF as with previousexamples. Results are as follows:

The DSC curve for the polymer of Example 5 shows a peak with a 119.6° C.melting point (Tm) with a heat of fusion of 60.0 J/g. The correspondingCRYSTAF curve shows the tallest peak at 47.6° C. with a peak area of59.5 percent. The delta between the DSC Tm and the Tcrystaf is 72.0° C.

The DSC curve for the polymer of Example 6 shows a peak with a 115.2° C.melting point (Tm) with a heat of fusion of 60.4 J/g. The correspondingCRYSTAF curve shows the tallest peak at 44.2° C. with a peak area of62.7 percent. The delta between the DSC Tm and the Tcrystaf is 71.0° C.

The DSC curve for the polymer of Example 7 shows a peak with a 121.3° C.melting point with a heat of fusion of 69.1 J/g. The correspondingCRYSTAF curve shows the tallest peak at 49.2° C. with a peak area of29.4 percent. The delta between the DSC Tm and the Tcrystaf is 72.1° C.

The DSC curve for the polymer of Example 8 shows a peak with a 123.5° C.melting point (Tm) with a heat of fusion of 67.9 J/g. The correspondingCRYSTAF curve shows the tallest peak at 80.1° C. with a peak area of12.7 percent. The delta between the DSC Tm and the Tcrystaf is 43.4° C.

The DSC curve for the polymer of Example 9 shows a peak with a 124.6° C.melting point (Tm) with a heat of fusion of 73.5 J/g. The correspondingCRYSTAF curve shows the tallest peak at 80.8° C. with a peak area of16.0 percent. The delta between the DSC Tm and the Tcrystaf is 43.8° C.

The DSC curve for the polymer of Example 10 shows a peak with a 115.6°C. melting point (Tm) with a heat of fusion of 60.7 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 40.9° C. with apeak area of 52.4 percent. The delta between the DSC Tm and the Tcrystafis 74.7° C.

The DSC curve for the polymer of Example 11 shows a peak with a 113.6°C. melting point (Tm) with a heat of fusion of 70.4 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 39.6° C. with apeak area of 25.2 percent. The delta between the DSC Tm and the Tcrystafis 74.1° C.

The DSC curve for the polymer of Example 12 shows a peak with a 113.2°C. melting point (Tm) with a heat of fusion of 48.9 J/g. Thecorresponding CRYSTAF curve shows no peak equal to or above 30° C.(Tcrystaf for purposes of further calculation is therefore set at 30°C.). The delta between the DSC Tm and the Tcrystaf is 83.2° C.

The DSC curve for the polymer of Example 13 shows a peak with a 114.4°C. melting point (Tm) with a heat of fusion of 49.4 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 33.8° C. with apeak area of 7.7 percent. The delta between the DSC Tm and the Tcrystafis 84.4° C.

The DSC for the polymer of Example 14 shows a peak with a 120.8° C.melting point (Tm) with a heat of fusion of 127.9 J/g. The correspondingCRYSTAF curve shows the tallest peak at 72.9° C. with a peak area of92.2 percent. The delta between the DSC Tm and the Tcrystaf is 47.9° C.

The DSC curve for the polymer of Example 15 shows a peak with a 114.3°C. melting point (Tm) with a heat of fusion of 36.2 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 32.3° C. with apeak area of 9.8 percent. The delta between the DSC Tm and the Tcrystafis 82.0° C.

The DSC curve for the polymer of Example 16 shows a peak with a 116.6°C. melting point (Tm) with a heat of fusion of 44.9 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 48.0° C. with apeak area of 65.0 percent. The delta between the DSC Tm and the Tcrystafis 68.6° C.

The DSC curve for the polymer of Example 17 shows a peak with a 116.0°C. melting point (Tm) with a heat of fusion of 47.0 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 43.1° C. with apeak area of 56.8 percent. The delta between the DSC Tm and the Tcrystafis 72.9° C.

The DSC curve for the polymer of Example 18 shows a peak with a 120.5°C. melting point (Tm) with a heat of fusion of 141.8 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 70.0° C. with apeak area of 94.0 percent. The delta between the DSC Tm and the Tcrystafis 50.5° C.

The DSC curve for the polymer of Example 19 shows a peak with a 124.8°C. melting point (Tm) with a heat of fusion of 174.8 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 79.9° C. with apeak area of 87.9 percent. The delta between the DSC Tm and the Tcrystafis 45.0° C.

The DSC curve for the polymer of Comparative D shows a peak with a 37.3°C. melting point (Tm) with a heat of fusion of 31.6 J/g. Thecorresponding CRYSTAF curve shows no peak equal to and above 30° C. Bothof these values are consistent with a resin that is low in density. Thedelta between the DSC Tm and the Tcrystaf is 7.3° C.

The DSC curve for the polymer of Comparative E shows a peak with a124.0° C. melting point (Tm) with a heat of fusion of 179.3 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 79.3° C. with apeak area of 94.6 percent. Both of these values are consistent with aresin that is high in density. The delta between the DSC Tm and theTcrystaf is 44.6° C.

The DSC curve for the polymer of Comparative F shows a peak with a124.8° C. melting point (Tm) with a heat of fusion of 90.4 J/g. Thecorresponding CRYSTAF curve shows the tallest peak at 77.6° C. with apeak area of 19.5 percent. The separation between the two peaks isconsistent with the presence of both a high crystalline and a lowcrystalline polymer. The delta between the DSC Tm and the Tcrystaf is47.2° C.

Physical Property Testing

Polymer samples are evaluated for physical properties such as hightemperature resistance properties, as evidenced by TMA temperaturetesting, pellet blocking strength, high temperature recovery, hightemperature compression set and storage modulus ratio, G′(25°C.)/G′(100° C.). Several commercially available polymers are included inthe tests: Comparative G* is a substantially linear ethylene/1-octenecopolymer (AFFINITY®, available from The Dow Chemical Company),Comparative H* is an elastomeric, substantially linear ethylene/1-octenecopolymer (AFFINITY®EG8100, available from The Dow Chemical Company),Comparative I is a substantially linear ethylene/1-octene copolymer(AFFINITY® PL1840, available from The Dow Chemical Company), ComparativeJ is hydrogenated styrene/butadiene/styrene triblock copolymer (Kraton™G1652, available from KRATON Polymers LLC), Comparative K is athermoplastic vulanizate (TPV, a polyolefin blend containing dispersedtherein a crosslinked elastomer). Results are presented in Table 4.TABLE 4 High Temperature Mechanical Properties Pellet 300% StrainCompres- TMA-1 mm Blocking Recovery sion Set penetration Strength G′(25°C.)/ (80° C.) (70° C.) Ex. (° C.) lb/ft² (kPa) G′(100° C.) (percent)(percent) D* 51 — 9 Failed — E* 130 — 18 — — F* 70 141 (6.8)  9 Failed100 5 104 0 (0)  6 81 49 6 110 — 5 — 52 7 113 — 4 84 43 8 111 — 4 Failed41 9 97 — 4 — 66 10 108 — 5 81 55 11 100 — 8 — 68 12 88 — 8 — 79 13 95 —6 84 71 14 125 — 7 — — 15 96 — 5 — 58 16 113 — 4 — 42 17 108 0 (0)  4 8247 18 125 — 10 — — 19 133 — 9 — — G* 75 463 (22.2) 89 Failed 100 H* 70213 (10.2) 29 Failed 100 I* 111 — 11 — — J* 107 — 5 Failed 100 K* 152 —3 — 40

In Table 4, Comparative F (which is a physical blend of the two polymersresulting from simultaneous polymerizations using catalyst A1 and B1)has a 1 mm penetration temperature of about 70° C., while Examples 5-9have a 1 mm penetration temperature of 100° C. or greater. Further,Examples 10-19 all have a 1 mm penetration temperature of greater than85° C., with most having 1 mm TMA temperature of greater than 90° C. oreven greater than 100° C. This shows that the novel polymers have betterdimensional stability at higher temperatures compared to a physicalblend. Comparative J (a commercial SEBS) has a good 1 mm TMA temperatureof about 107° C., but it has very poor (high temperature 70° C.)compression set of about 100 percent and it also failed to recover(sample broke) during a high temperature (80° C.) 300 percent strainrecovery. Thus the exemplified polymers have a unique combination ofproperties unavailable even in some commercially available, highperformance thermoplastic elastomers.

Similarly, Table 4 shows a low (good) storage modulus ratio, G′(25°C.)/G′(100° C.), for the inventive polymers of 6 or less, whereas aphysical blend (Comparative F) has a storage modulus ratio of 9 and arandom ethylene/octene copolymer (Comparative G) of similar density hasa storage modulus ratio an order of magnitude greater (89). It isdesirable that the storage modulus ratio of a polymer be as close to 1as possible. Such polymers will be relatively unaffected by temperature,and fabricated articles made from such polymers can be usefully employedover a broad temperature range. This feature of low storage modulusratio and temperature independence is particularly useful in elastomerapplications such as in pressure sensitive adhesive formulations.

The data in Table 4 also demonstrate that the polymers of the inventionpossess improved pellet blocking strength. In particular, Example 5 hasa pellet blocking strength of 0 MPa, meaning it is free flowing underthe conditions tested, compared to Comparatives F and G which showconsiderable blocking. Blocking strength is important since bulkshipment of polymers having large blocking strengths can result inproduct clumping or sticking together upon storage or shipping,resulting in poor handling properties.

High temperature (70° C.) compression set for the inventive polymers isgenerally good, meaning generally less than about 80 percent, preferablyless than about 70 percent and especially less than about 60 percent. Incontrast, Comparatives F, G, H and J all have a 70° C. compression setof 100 percent (the maximum possible value, indicating no recovery).Good high temperature compression set (low numerical values) isespecially needed for applications such as gaskets, window profiles,o-rings, and the like. TABLE 5 Ambient Temperature Mechanical PropertiesElonga- Elonga- Tensile 100% 300% Retractive Com- tion tion Abrasion:Notched Strain Strain Stress pression Stress Flex Tensile Tensile atTensile at Volume Tear Recovery Recovery at 150 Set Relaxation ModulusModulus Strength Break¹ Strength Break Loss Strength 21° C. 21° C. %Strain 21° C. at 50% Ex. (MPa) (MPa) (MPa)¹ (%) (MPa) (%) (mm³) (mJ)(percent) (percent) (kPa) (Percent) Strain² D* 12 5 — — 10 1074 — — 9183 760 — — E* 895 589 — 31 1029 — — — — — — — F* 57 46 — — 12 824 93 33978 65 400 42 — 5 30 24 14 951 16 1116 48 — 87 74 790 14 33 6 33 29 — —14 938 — — — 75 861 13 — 7 44 37 15 846 14 854 39 — 82 73 810 20 — 8 4135 13 785 14 810 45 461 82 74 760 22 — 9 43 38 — — 12 823 — — — — — 25 —10 23 23 — — 14 902 — — 86 75 860 12 — 11 30 26 — — 16 1090 — 976 89 66510 14 30 12 20 17 12 961 13 931 — 1247 91 75 700 17 — 13 16 14 — — 13814 — 691 91 — — 21 — 14 212 160 — — 29 857 — — — — — — — 15 18 14 121127 10 1573 — 2074 89 83 770 14 — 16 23 20 — — 12 968 — — 88 83 1040 13— 17 20 18 — — 13 1252 — 1274 13 83 920 4 — 18 323 239 — — 30 808 — — —— — — — 19 706 483 — — 36 871 — — — — — — — G* 15 15 — — 17 1000 — 74686 53 110 27 50 H* 16 15 — — 15 829 — 569 87 60 380 23 — I* 210 147 — —29 697 — — — — — — — J* — — — — 32 609 — — 93 96 1900 25 — K* — — — — —— — — — — — 30 —¹Tested at 51 cm/minute²measured at 38° C. for 12 hours

Table 5 shows results for mechanical properties for the new polymers aswell as for various comparison polymers at ambient temperatures. It maybe seen that the inventive polymers have very good abrasion resistancewhen tested according to ISO 4649, generally showing a volume loss ofless than about 90 mm, preferably less than about 80 mm³, and especiallyless than about 50 mm³. In this test, higher numbers indicate highervolume loss and consequently lower abrasion resistance.

Tear strength as measured by tensile notched tear strength of theinventive polymers is generally 1000 mJ or higher, as shown in Table 5.Tear strength for the inventive polymers can be as high as 3000 mJ, oreven as high as 5000 mJ. Comparative polymers generally have tearstrengths no higher than 750 mJ.

Table 5 also shows that the polymers of the invention have betterretractive stress at 150 percent strain (demonstrated by higherretractive stress values) than some of the comparative samples.Comparative Examples F, G and H have retractive stress value at 150percent strain of 400 kPa or less, while the inventive polymers haveretractive stress values at 150 percent strain of 500 kPa (Ex. 11) to ashigh as about 1100 kPa (Ex. 17). Polymers having higher than 150 percentretractive stress values would be quite useful for elastic applications,such as elastic fibers and fabrics, especially nonwoven fabrics. Otherapplications include diaper, hygiene, and medical garment waistbandapplications, such as tabs and elastic bands.

Table 5 also shows that stress relaxation (at 50 percent strain) is alsoimproved (less) for the inventive polymers as compared to, for example,Comparative G. Lower stress relaxation means that the polymer retainsits force better in applications such as diapers and other garmentswhere retention of elastic properties over long time periods at bodytemperatures is desired.

Optical Testing TABLE 6 Polymer Optical Properties Ex. Internal Haze(percent) Clarity (percent) 45° Gloss (percent) F* 84 22 49 G* 5 73 56 513 72 60 6 33 69 53 7 28 57 59 8 20 65 62 9 61 38 49 10 15 73 67 11 1369 67 12 8 75 72 13 7 74 69 14 59 15 62 15 11 74 66 16 39 70 65 17 29 7366 18 61 22 60 19 74 11 52 G* 5 73 56 H* 12 76 59 I* 20 75 59

The optical properties reported in Table 6 are based on compressionmolded films substantially lacking in orientation. Optical properties ofthe polymers may be varied over wide ranges, due to variation incrystallite size, resulting from variation in the quantity of chainshuttling agent employed in the polymerization.

Extractions of Multi-Block Copolymers

Extraction studies of the polymers of Examples 5, 7 and Comparative Eare conducted. In the experiments, the polymer sample is weighed into aglass fritted extraction thimble and fitted into a Kumagawa typeextractor. The extractor with sample is purged with nitrogen, and a 500mL round bottom flask is charged with 350 mL of diethyl ether. The flaskis then fitted to the extractor. The ether is heated while beingstirred. Time is noted when the either begins to condense into thethimble, and the extraction is allowed to proceed under nitrogen for 24hours. At this time, heating is stopped and the solution is allowed tocool. Any either remaining in the extractor is returned to the flask.The ether in the flask is evaporated under vacuum at ambienttemperature, and the resulting solids are purged dry with nitrogen. Anyresidue is transferred to a weighed bottle using successive washes ofhexane. The combined hexane washes are then evaporated with anothernitrogen purge, and the residue dried under vacuum overnight at 40° C.Any remaining ether in the extractor is purged dry with nitrogen.

A second clean round bottom flask charged with 350 mL of hexane is thenconnected to the extractor. The hexane is heated to reflux with stirringand maintained at reflux for 24 hours after hexane is first noticedcondensing into the thimble. Heating is then stopped and the flask isallowed to cool. Any hexane remaining in the extractor is transferredback to the flask. The hexane is removed by evaporation under vacuum atambient temperature, and any residue remaining in the flask istransferred to a weighed bottle using successive hexane washes. Thehexane in the flask is evaporated by a nitrogen purge, and the residueis vacuum dried overnight at 40° C.

The polymer sample remaining in the thimble after the extractions istransferred from the thimble to a weighed bottle and vacuum driedovernight at 40° C. Results are contained in Table 7. TABLE 7 etherether C₈ hexane hexane C₈ residue wt. soluble soluble mole solublesoluble mole C₈ mole Sample (g) (g) (percent) percent¹ (g) (percent)percent¹ percent¹ Comp. F* 1.097 0.063 5.69 12.2 0.245 22.35 13.6 6.5Ex. 5 1.006 0.041 4.08 — 0.040 3.98 14.2 11.6 Ex. 7 1.092 0.017 1.5913.3 0.012 1.10 11.7 9.9¹Determined by ¹³C NMR

ADDITIONAL POLYMER EXAMPLES 19A-J, CONTINUOUS SOLUTION POLYMERIZATION,CATALYST A1/B2+DEZ FOR EXAMPLES 19A-I

Continuous solution polymerizations are carried out in a computercontrolled well-mixed reactor. Purified mixed alkanes solvent (Isopar™ Eavailable from ExxonMobil Chemical Company), ethylene, 1-octene, andhydrogen (where used) are combined and fed to a 27 gallon reactor. Thefeeds to the reactor are measured by mass-flow controllers. Thetemperature of the feed stream is controlled by use of a glycol cooledheat exchanger before entering the reactor. The catalyst componentsolutions are metered using pumps and mass flow meters. The reactor isrun liquid-full at approximately 550 psig pressure. Upon exiting thereactor, water and additive are injected in the polymer solution. Thewater hydrolyzes the catalysts, and terminates the polymerizationreactions. The post reactor solution is then heated in preparation for atwo-stage devolatization. The solvent and unreacted monomers are removedduring the devolatization process. The polymer melt is pumped to a diefor underwater pellet cutting.

FOR EXAMPLE 19J

Continuous solution polymerizations are carried out in a computercontrolled autoclave reactor equipped with an internal stirrer. Purifiedmixed alkanes solvent (Isopar™ E available from ExxonMobil ChemicalCompany), ethylene at 2.70 lbs/hour (1.22 kg/hour), 1-octene, andhydrogen (where used) are supplied to a 3.8 L reactor equipped with ajacket for temperature control and an internal thermocouple. The solventfeed to the reactor is measured by a mass-flow controller. A variablespeed diaphragm pump controls the solvent flow rate and pressure to thereactor. At the discharge of the pump, a side stream is taken to provideflush flows for the catalyst and cocatalyst injection lines and thereactor agitator. These flows are measured by Micro-Motion mass flowmeters and controlled by control valves or by the manual adjustment ofneedle valves. The remaining solvent is combined with 1-octene,ethylene, and hydrogen (where used) and fed to the reactor. A mass flowcontroller is used to deliver hydrogen to the reactor as needed. Thetemperature of the solvent/monomer solution is controlled by use of aheat exchanger before entering the reactor. This stream enters thebottom of the reactor. The catalyst component solutions are meteredusing pumps and mass flow meters and are combined with the catalystflush solvent and introduced into the bottom of the reactor. The reactoris run liquid-full at 500 psig (3.45 MPa) with vigorous stirring.Product is removed through exit lines at the top of the reactor. Allexit lines from the reactor are steam traced and insulated.Polymerization is stopped by the addition of a small amount of waterinto the exit line along with any stabilizers or other additives andpassing the mixture through a static mixer. The product stream is thenheated by passing through a heat exchanger before devolatilization. Thepolymer product is recovered by extrusion using a devolatilizingextruder and water cooled pelletizer.

Process details and results are contained in Table 8. Selected polymerproperties are provided in Tables 9A-B.

In Table 9B, inventive examples 19F and 19G show low immediate set ofaround 65-70% strain after 500% elongation. TABLE 8 PolymerizationConditions Cat Cat Cat Cat A1² A1 B2³ B2 DEZ C₂H₄ C₈H₁₆ Solv. H₂ T Conc.Flow Conc. Flow Conc Ex. lb/hr lb/hr lb/hr sccm¹ ° C. ppm lb/hr ppmlb/hr wt % 19A 55.29 32.03 323.03 101 120 600 0.25 200 0.42 3.0 19B53.95 28.96 325.3 577 120 600 0.25 200 0.55 3.0 19C 55.53 30.97 324.37550 120 600 0.216 200 0.609 3.0 19D 54.83 30.58 326.33 60 120 600 0.22200 0.63 3.0 19E 54.95 31.73 326.75 251 120 600 0.21 200 0.61 3.0 19F50.43 34.80 330.33 124 120 600 0.20 200 0.60 3.0 19G 50.25 33.08 325.61188 120 600 0.19 200 0.59 3.0 19H 50.15 34.87 318.17 58 120 600 0.21 2000.66 3.0 19I 55.02 34.02 323.59 53 120 600 0.44 200 0.74 3.0 19J 7.469.04 50.6 47 120 150 0.22 76.7 0.36 0.5 Cocat Cocat Cocat Cocat [Zn]⁴DEZ 1 1 2 2 in Poly Flow Conc. Flow Conc. Flow polymer Rate⁵ Conv⁶Polymer Ex. lb/hr ppm lb/hr ppm lb/hr ppm lb/hr wt % wt % Eff.⁷ 19A 0.704500 0.65 525 0.33 248 83.94 88.0 17.28 297 19B 0.24 4500 0.63 525 0.1190 80.72 88.1 17.2 295 19C 0.69 4500 0.61 525 0.33 246 84.13 88.9 17.16293 19D 1.39 4500 0.66 525 0.66 491 82.56 88.1 17.07 280 19E 1.04 45000.64 525 0.49 368 84.11 88.4 17.43 288 19F 0.74 4500 0.52 525 0.35 25785.31 87.5 17.09 319 19G 0.54 4500 0.51 525 0.16 194 83.72 87.5 17.34333 19H 0.70 4500 0.52 525 0.70 259 83.21 88.0 17.46 312 19I 1.72 45000.70 525 1.65 600 86.63 88.0 17.6 275 19J 0.19 — — — — — — — — —¹standard cm³/min²[N-(2,6-di(1-methylethyl)phenyl)amido)(2-isopropylphenyl)(α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)]hafniumdimethyl³bis-(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)immino)zirconiumdimethyl⁴ppm in final product calculated by mass balance⁵polymer production rate⁶weight percent ethylene conversion in reactor⁷efficiency, kg polymer/g M where g M = g Hf = g Z

TABLE 9A Polymer Physical Properties Heat of CRYSTAF Density Mw MnFusion Tm Tc TCRYSTAF Tm − TCRYSTAF Peak Area Ex. (g/cc) I₂ I₁₀ I₁₀/I₂(g/mol) (g/mol) Mw/Mn (J/g) (° C.) (° C.) (° C.) (° C.) (wt %) 19A0.8781 0.9 6.4 6.9 123700 61000 2.0 56 119 97 46 73 40 19B 0.8749 0.97.3 7.8 133000 44300 3.0 52 122 100 30 92 76 19C 0.8753 5.6 38.5 6.981700 37300 2.2 46 122 100 30 92 8 19D 0.8770 4.7 31.5 6.7 80700 397002.0 52 119 97 48 72 5 19E 0.8750 4.9 33.5 6.8 81800 41700 2.0 49 121 9736 84 12 19F 0.8652 1.1 7.5 6.8 124900 60700 2.1 27 119 88 30 89 89 19G0.8649 0.9 6.4 7.1 135000 64800 2.1 26 120 92 30 90 90 19H 0.8654 1.07.0 7.1 131600 66900 2.0 26 118 88 — — — 19I 0.8774 11.2 75.2 6.7 6640033700 2.0 49 119 99 40 79 13 19J 0.8995 5.6 39.4 7.0 75500 29900 2.5 101122 106 — — —

TABLE 9B Polymer Physical Properties of Compression Molded FilmsImmediate Immediate Immediate Set after Set after Set after RecoveryRecovery Recovery 100% Strain 300% Strain 500% Strain after 100% after300% after 500% Example (%) (%) (%) (%) (%) (%) 19A 15 63 131 85 79 7419B 14 49 97 86 84 81 19F — — 70 — 87 86 19G — — 66 — — 87 19H — 39 — —87 —

TABLE 9C Average Block Index For exemplary polymers¹ Example Zn/C₂ ²Average BI Polymer F 0 0 Polymer 8 0.56 0.59 Polymer 19a 1.3 0.62Polymer 5 2.4 0.52 Polymer 19b 0.56 0.54 Polymer 19h 3.15 0.59¹Additional information regarding the calculation of the block indicesfor various polymers is disclosed in U.S. patent application Ser. No.11/376,835, entitled “Ethylene/α-Olefin Block Interpolymers”, filed onMar. 15, 2006, in the name of Colin L. P. Shan, Lonnie Hazlitt, et. al.,the disclosure of which is incorporated by reference herein in itsentirety.²Zn/C₂ *1000 = (Zn feed flow*Zn concentration/1000000/Mw of Zn)/(TotalEthylene feed flow*(1 − fractional ethylene conversion rate)/Mw ofEthylene)*1000.Please note that “Zn” in “Zn/C₂*1000” refers to the amount of zinc indiethyl zinc (“DEZ”) used in the polymerization process, and “C₂” refersto the amount of ethylene used in the polymerization process.Fibers and Articles of Manufacture

Various homofil fibers can be made from the inventive blockinterpolymers (also referred to hereinafter as “copolymer(s)”),including staple fibers, spunbond fibers or melt blown fibers (using,e.g., systems as disclosed in U.S. Pat. Nos. 4,340,563, 4,663,220,4,668,566 or 4,322,027, and gel spun fibers (e.g., the system disclosedin U.S. Pat. No. 4,413,110). Staple fibers can be melt spun into thefinal fiber diameter directly without additional drawing, or they can bemelt spun into a higher diameter and subsequently hot or cold drawn tothe desired diameter using conventional fiber drawing techniques.

Bicomponent fibers can also be made from the block copolymers accordingto some embodiments of the invention. Such bicomponent fibers have theinventive block interpolymer in at least one portion of the fiber. Forexample, in a sheath/core bicomponent fiber (i.e., one in which thesheath concentrically surrounds the core), the inventive blend with theblock interpolymer can be in either the sheath or the core. Typicallyand preferably, the copolymer blend is the sheath component of thebicomponent fiber but if it is the core component, then the sheathcomponent must be such that it does not prevent the crosslinking of thecore, i.e., the sheath component is transparent or translucent toUV-radiation such that sufficient UV-radiation can pass through it tosubstantially crosslink the core polymer. Different copolymers can alsobe used independently as the sheath and the core in the same fiber,preferably where both components are elastic and especially where thesheath component has a lower melting point than the core component.Other types of bicomponent fibers are within the scope of the inventionas well, and include such structures as side-by-side conjugated fibers(e.g., fibers having separate regions of polymers, wherein the inventiveblock interpolymer comprises at least a portion of the fiber's surface).

The shape of the fiber is not limited. For example, typical fiber has acircular cross-sectional shape, but sometimes fibers have differentshapes, such as a trilobal shape, or a flat (i.e., “ribbon” like) shape.The fiber disclosed herein is not limited by the shape of the fiber.

Fiber diameter can be measured and reported in a variety of fashions.Generally, fiber diameter is measured in denier per filament. Denier isa textile term which is defined as the grams of the fiber per 9000meters of that fiber's length. Monofilament generally refers to anextruded strand having a denier per filament greater than 15, usuallygreater than 30. Fine denier fiber generally refers to fiber having adenier of about 15 or less. Microdenier (aka microfiber) generallyrefers to fiber having a diameter not greater than about 100micrometers. For the fibers according to some embodiments of theinvention, the diameter can be widely varied, with little impact uponthe elasticity of the fiber. The fiber denier, however, can be adjustedto suit the capabilities of the finished article and as such, wouldpreferably be: from about 0.5 to about 30 denier/filament for meltblown; from about 1 to about 30 denier/filament for spunbond; and fromabout 1 to about 20,000 denier/filament for continuous wound filament.Nonetheless, preferably, the denier is greater than 40, more preferablygreater than or equal to 55 and most preferably greater than or equal to65. These preferences are due to the fact that typically durable apparelemploy fibers with deniers greater than about 40.

The elastic copolymer can also be shaped or fabricated into elasticfilms, coatings, sheets, strips, tapes, ribbons and the like. Suchelastic film, coating and sheet may be fabricated by any method known inthe art, including blown bubble processes (e.g., simple bubble as wellas biaxial orientation techniques such trapped bubble, double bubble andtenter framing), cast extrusion, injection molding processes,thermoforming processes, extrusion coating processes, profile extrusion,and sheet extrusion processes. Simple blown bubble film processes aredescribed, for example, in The Encyclopedia of Chemical Technology,Kirk-Othmer, Third Edition, John Wiley & Sons, New York, 1981, Vol. 16,pp. 416-417 and Vol. 18, pp. 191-192. The cast extrusion method isdescribed, for example, in Modern Plastics Mid-October 1989 EncyclopediaIssue, Volume 66, Number 11, pages 256 to 257. Injection molding,thermoforming, extrusion coating, profile extrusion, and sheet extrusionprocesses are described, for example, in Plastics Materials andProcesses, Seymour

S. Schwartz and Sidney H. Goodman, Van Nostrand Reinhold Company, NewYork, 1982, pp. 527-563, pp. 632-647, and pp. 596-602.

The elastic strips, tapes and ribbons can be prepared by any knownmethod, including the direct extrusion processing or by post-extrusionslitting, cutting or stamping techniques. Profile extrusion is anexample of a primary extrusion process that is particularly suited tothe preparation of tapes, bands, ribbons and the like.

The fibers according to embodiments of the invention can be used withother fibers such as PET, nylon, cotton, Kevlar™, etc. to make elasticfabrics. As an added advantage, the heat (and moisture) resistance ofcertain fibers can enable polyester PET fibers to be dyed at ordinaryPET dyeing conditions. The other commonly used fibers, especiallyspandex (e.g., Lycra™), can only be used at less severe PET dyeingconditions to prevent degradation of properties.

Fabrics made from the fibers according to embodiments of the inventioninclude woven, nonwoven and knit fabrics, including circular knitted,warp knitted and flat knitted fabrics. Nonwoven fabrics can be madevarious by methods, e.g., spunlaced (or hydrodynamically entangled)fabrics as disclosed in U.S. Pat. Nos. 3,485,706 and 4,939,016, cardingand thermally bonding staple fibers; spunbonding continuous fibers inone continuous operation; or by melt blowing or spinning fibers intofabric and subsequently calandering or thermally bonding the resultantweb. These various nonwoven fabric manufacturing techniques are known tothose skilled in the art and the disclosure is not limited to anyparticular method. Other structures made from such fibers are alsoincluded within the scope of the invention, including e.g., blends ofthese novel fibers with other fibers (e.g., poly(ethylene terephthalate)or cotton).

Nonwoven fabrics can be made from fibers obtained from solution spinningor flash spinning the inventive ethylene/α-olefin interpolmers. Solutionspinning includes wet spinning and dry spinning. In both methods, aviscous solution of polymer is pumped through a filter and then passedthrough the fine holes of a spinnerette. The solvent is subsequentlyremoved, leaving a fiber.

In some embodiments, the following process is used for flash spinningfibers and forming sheets from an inventive ethylene/α-olefininterpolymer. The basic system has been previously disclosed in U.S.Pat. No. 3,860,369 and No. 6,117,801, which are hereby incorporated byreference herein in their entirety. The process is conducted in achamber, sometimes referred to as a spin cell, which has a vapor-removalport and an opening through which non-woven sheet material produced inthe process is removed. Polymer solution (or spin liquid) iscontinuously or batchwise prepared at an elevated temperature andpressure and provided to the spin cell via a conduit. The pressure ofthe solution is greater than the cloud-point pressure which is thelowest pressure at which the polymer is fully dissolved in the spinagent forming a homogeneous single phase mixture.

The single phase polymer solution passes through a letdown orifice intoa lower pressure (or letdown) chamber. In the lower pressure chamber,the solution separates into a two-phase liquid-liquid dispersion. Onephase of the dispersion is a spin agent-rich phase which comprisesprimarily the spin agent and the other phase of the dispersion is apolymer-rich phase which contains most of the polymer. This two phaseliquid-liquid dispersion is forced through a spinneret into an area ofmuch lower pressure (preferably atmospheric pressure) where the spinagent evaporates very rapidly (flashes), and the polymer emerges fromthe spinneret as a yarn (or plexifilament). The yarn is stretched in atunnel and is directed to impact a rotating baffle. The rotating bafflehas a shape that transforms the yarn into a flat web, which is about5-15 cm wide, and separating the fibrils to open up the web. Therotating baffle further imparts a back and forth oscillating motionhaving sufficient amplitude to generate a wide back and forth swath. Theweb is laid down on a moving wire lay-down belt located about 50 cmbelow the spinneret, and the back and forth oscillating motion isarranged to be generally across the belt to form a sheet.

As the web is deflected by the baffle on its way to the moving belt, itenters a corona charging zone between a stationary multi-needle ion gunand a grounded rotating target plate. The multi-needle ion gun ischarged to a DC potential of by a suitable voltage source. The chargedweb is carried by a high velocity spin agent vapor stream through adiffuser comprising two parts: a front section and a back section. Thediffuser controls the expansion of the web and slows it down. The backsection of the diffuser may be stationary and separate from targetplate, or it may be integral with it. In the case where the back sectionand the target plate are integral, they rotate together. Aspirationholes are drilled in the back section of the diffuser to assure adequateflow of gas between the moving web and the diffuser back section toprevent sticking of the moving web to the diffuser back section. Themoving belt is grounded through rolls so that the charged web iselectrostatically attracted to the belt and held in place thereon.Overlapping web swaths collected on the moving belt and held there byelectrostatic forces are formed into a sheet with a thickness controlledby the belt speed. The sheet is compressed between the belt and theconsolidation roll into a structure having sufficient strength to behandled outside the chamber and then collected outside the chamber on awindup roll.

Accordingly, some embodiments of the invention provide a soft polymericflash-spun plexifilamentary material comprising an inventiveethylene/α-olefin interpolymer described herein. Preferably, theethylene/α-olefin interpolymer has a melt index from about 0.1 to about50 g/10 min or from about 0.4 to about 10 g/10 min and a density fromabout 0.85 to about 0.95 g/cc or from about 0.87 and about 0.90 g/cc.Preferably, the molecular weight distribution of the interpolymer isgreater than about 1 but less than about four. Moreover, the flash-spunplexifilamentary material has a BET surface area of greater than about 2m²/g or greater than about 8 m²/g. A soft flash-spun nonwoven sheetmaterial can be made from the soft polymeric flash-spun plexifilamentarymaterial. The soft flash-spun nonwoven sheet material can be spunbonded,area bonded, or pointed bonded. Other embodiments of the inventionprovide a soft polymeric flash-spun plexifilamentary material comprisingan ethylene/α-alpha interpolymer (described herein) blended with highdensity polyethylene polymer, wherein the ethylene/α-alpha interpolymerhas a melt index of between about 0.4 and about 10 g/10 min, a densitybetween about 0.87 and about 0.93 g/cc, and a molecular weightdistribution less than about 4, and wherein the plexifilamentarymaterial has a BET surface area greater than about 8 m²/g. The softflash-spun nonwoven sheet has an opacity of at least 85%.

Flash-spun nonwoven sheets made by the above process or a similarprocess can used to replace Tyvek® spunbonded olefin sheets for airinfiltration barriers in construction applications, as packaging such asair express envelopes, as medical packaging, as banners, and forprotective apparel and other uses.

Fabricated articles which can be made using the fibers and fabricsaccording to embodiments of the invention include elastic compositearticles (e.g., diapers) that have elastic portions. For example,elastic portions are typically constructed into diaper waist bandportions to prevent the diaper from falling and leg band portions toprevent leakage (as shown in U.S. Pat. No. 4,381,781, the disclosure ofwhich is incorporated herein by reference). Often, the elastic portionspromote better form fitting and/or fastening systems for a goodcombination of comfort and reliability. The inventive fibers and fabricscan also produce structures which combine elasticity with breathability.For example, the inventive fibers, fabrics and/or films may beincorporated into the structures disclosed in U.S. provisional patentapplication 60/083,784, filed May 1, 1998. Laminates of non-wovenscomprising fibers of the invention can also be formed and can be used invarious articles, including consumer goods, such as durables anddisposable consumers goods, like apparel, diapers, hospital gowns,hygiene applications, upholstery fabrics, etc.

The inventive fibers, films and fabrics can also be used in variousstructures as described in U.S. Pat. No. 2,957,512. For example, layer50 of the structure described in the preceding patent (i.e., the elasticcomponent) can be replaced with the inventive fibers and fabrics,especially where flat, pleated, creped, crimped, etc., nonelasticmaterials are made into elastic structures. Attachment of the inventivefibers and/or fabric to nonfibers, fabrics or other structures can bedone by melt bonding or with adhesives. Gathered or shirted elasticstructures can be produced from the inventive fibers and/or fabrics andnonelastic components by pleating the non-elastic component (asdescribed in U.S. Pat. No. 2,957,512) prior to attachment,pre-stretching the elastic component prior to attachment, or heatshrinking the elastic component after attachment.

The inventive fibers also can be used in a spunlaced (orhydrodynamically entangled) process to make novel structures. Forexample, U.S. Pat. No. 4,801,482 discloses an elastic sheet (12) whichcan now be made with the novel fibers/films/fabric described herein.

Continuous elastic filaments as described herein can also be used inwoven or knit applications where high resilience is desired.

U.S. Pat. No. 5,037,416 describes the advantages of a form fitting topsheet by using elastic ribbons (see member 19 of U.S. Pat. No.5,037,416). The inventive fibers could serve the function of member 19of U.S. Pat. No. 5,037,416, or could be used in fabric form to providethe desired elasticity.

In U.S. Pat. No. 4,981,747 (Morman), the inventive fibers and/or fabricsdisclosed herein can be substituted for elastic sheet 122, which forms acomposite elastic material including a reversibly necked material.

The inventive fibers can also be a melt blown elastic component, asdescribed in reference 6 of the drawings of U.S. Pat. No. 4,879,170.

Elastic panels can also be made from the inventive fibers and fabricsdisclosed herein, and can be used, for example, as members 18, 20, 14,and/or 26 of U.S. Pat. No. 4,940,464. The inventive fibers and fabricsdescribed herein can also be used as elastic components of compositeside panels (e.g., layer 86 of the patent).

The elastic materials can also be rendered pervious or “breathable” byany method known in the art including by apperturing, slitting,microperforating, mixing with fibers or foams, or the like andcombinations thereof. Examples of such methods include, U.S. Pat. No.3,156,242 by Crowe, Jr., U.S. Pat. No. 3,881,489 by Hartwell, U.S. Pat.No. 3,989,867 by Sisson and U.S. Pat. No. 5,085,654 by Buell.

The fibers in accordance with certain embodiments of the invention caninclude covered fibers. Covered fibers comprise a core and a cover.Generally, the core comprises one or more elastic fibers, and the covercomprises one or more inelastic fibers. At the time of the constructionof the covered fiber and in their respective unstretched states, thecover is longer, typically significantly longer, than the core fiber.The cover surrounds the core in a conventional manner, typically in aspiral wrap configuration. Uncovered fibers are fibers without a cover.Generally, a braided fiber or yarn, i.e., a fiber comprising two or morefiber strands or filaments (elastic and/or inelastic) of about equallength in their respective unstretched states intertwined with ortwisted about one another, is not a covered fiber. These yarns can,however, be used as either or both the core and cover of the coveredfiber. In other embodiments, covered fibers may comprise an elastic corewrapped in an elastic cover.

Full or substantial reversibility of heat-set stretch imparted to afiber or fabric made from the fiber can be a useful property. Forexample, if a covered fiber can be heat-set before dyeing and/orweaving, then the dyeing and/or weaving processes are more efficientbecause the fiber is less likely to stretch during winding operations.This, in turn, can be useful in dyeing and weaving operations in whichthe fiber is first wound onto a spool. Once the dyeing and/or weaving iscompleted, then the covered fiber or fabric comprising the covered fibercan be relaxed. Not only does this technique reduce the amount of fibernecessary for a particular weaving operation, but it will also guardagainst subsequent shrinkage. Such reversible, heat-set, elastic fibers,and methods of making the fibers and articles made from such fibers aredisclosed in U.S. patent application Ser. No. 10/507,230 (published asUS 20050165193), which is incorporated by reference herein in itsentirety. Such methods can also be used in embodiments of the inventionwith or without modifications to make reversible, heat-set, elasticfibers, fabrics, and articles made therefrom.

Preactivated articles can be made according to the teachings of U.S.Pat. No. 5,226,992, U.S. Pat. No. 4,981,747 (KCC, Morman), and U.S. Pat.No. 5,354,597, all of which are incorporated by reference herein intheir entirety.

High tenacity fibers can be made according to the teachings of U.S. Pat.No. 6,113,656, U.S. Pat. No. 5,846,654, and U.S. Pat. No. 5,840,234, allof which are incorporated by reference herein in their entirety.

Low denier fibers, including microdenier fibers, can be made from theinventive interpolymers.

The preferred use of the inventive fibers, is in the formation offabric, both woven and non-woven fabrics. Fabrics formed from the fibershave been found to have excellent elastic properties making themsuitable for many garment applications. They also have gooddrapeability.

Some of the desirable properties of fibers and fabric may be expressedin terms of tensile modulus and permanent set. For a spunbonded fabricaccording to certain embodiments of the invention, the preferredproperties which are obtained are as follows:

Tensile modulus (g) (ASTM-1682) (100% extension, 6 cycles, machinedirection (MD)): preferably less than 900, more preferably less than800, most preferably from 100 to 400; and/or

Tensile modulus (g) (50% extension, 6 cycles, MD): preferably less than700, more preferably less than 600, most preferably from 100 to 300;and/or

Tensile modulus (g) (100% extension, 6 cycles, transverse direction(TD)): preferably less than 600, more preferably less than 500, mostpreferably from 50 to 300; and/or

Tensile modulus (g) (50% extension, 6 cycles, TD): preferably less than370, more preferably from 40 to 200; and/or

Permanent set (%) (obtained through use of a modification of ASTM D-1682wherein the stretching is cycled rather than continued through fabricfailure) (50% extension, 6 cycles, MD): preferably less than 30, morepreferably in the range of about 5-about 25%, most preferably less than10-20; and/or

Permanent set (%) (50% extension, 6 cycles, TD): preferably less than35%, more preferably in the range of about 5-about 25%; and/or

Permanent set (%) (100% extension, 6 cycles, MD): preferably less than40%, more preferably in the range of about 5-about 35%, most preferably8-20%; and/or

Permanent set (%) (100% extension, 6 cycles, TD): preferably less than40%, more preferably in the range of about 5-about 35%, most preferablyin the range of about 5-25%; and/or

Bond Temperature (° C.) less than 110, more preferably in the range ofabout 35-about 105, most preferably from 40-80. These properties arepreferred and have utility for all fabrics of the invention, and aredemonstrated, for example, by a fabric made from fibers according tocertain embodiments of the invention and having a basis weight of about70 to about 80 g/m², preferably about 70 g/m² and formed from fibershaving diameter of about 25-28.μm.

For meltblown fabric, according to certain embodiments of the invention,the preferred properties follow:

Permanent set (%) (50% extension, 6 cycles, MD): preferably less than25, more preferably in the range of about 10-about 20, most preferably15-18; and/or

Permanent set (%) (50% extension, 6 cycles, TD): preferably less thanabout 25, more preferably in the range of about 10-about 20, mostpreferably 15-18; and/or

Tensile modulus (g) (50% extension, 6 cycles, MD): preferably not morethan about 300, more preferably in the range of about 200-about 300;and/or

Tensile modulus (g) (50% extension, 6 cycles, TD): preferably less thanabout 300, more preferably in the range of about 50-about 150; about150; and/or

Total Hand (g): preferably less than about 75, more preferably less thanabout 70, most preferably in the range of about 10-about 20.

These properties are preferred and have utility for certain fabrics madein some embodiments of the invention, and are demonstrated, for example,by meltblown fabric with nominal basis weight of about 70 g/m², madefrom fibers of 8-10 μm diameter.

Blending with Another Polymer

The ethylene/α-olefin block interpolymers can be blended with at leastanother polymer, such as a polyolefin (e.g., polypropylene) to makefibers, such as described above. This second polymer is different fromthe ethylene/α-olefin block interpolymer in composition (comonomer type,comonomer content, etc.), structure, property, or a combination of both.For example, a block ethylene/octene copolymer is different than arandom ethylene/octene copolymer, even if they have the same amount ofcomonomers. A block ethylene/octene copolymer is different than anethylene/butane copolymer, regardless of whether it is a random or blockcopolymer or whether it has the same comonomer content. Two polymersalso are considered different if they have a different molecular weight,even if they have the same structure and composition.

A polyolefin is a polymer derived from two or more olefins (i.e.,alkenes). An olefin (i.e., alkene) is a hydrocarbon containing at leastone carbon-carbon double bond. The olefin can be a monoene (i.e., anolefin having a single carbon-carbon double bond), diene (i.e., anolefin having two carbon-carbon double bonds), triene (i.e., an olefinhaving three carbon-carbon double bonds), tetraene (i.e., an olefinhaving four carbon-carbon double bonds), and other polyenes. The olefinor alkene, such as monoene, diene, triene, tetraene and other polyenes,can have 3 or more carbon atoms, 4 or more carbon atoms, 6 or morecarbon atoms, 8 or more carbon atoms. In some embodiments, the olefinhas from 3 to about 100 carbon atoms, from 4 to about 100 carbon atoms,from 6 to about 100 carbon atoms, from 8 to about 100 carbon atoms, from3 to about 50 carbon atoms, from 3 to about 25 carbon atoms, from 4 toabout 25 carbon atoms, from 6 to about 25 carbon atoms, from 8 to about25 carbon atoms, or from 3 to about 10 carbon atoms. In someembodiments, the olefin is a linear or branched, cyclic or acyclic,monoene having from 2 to about 20 carbon atoms. In other embodiments,the alkene is a diene such as butadiene and 1,5-hexadiene. In furtherembodiments, at least one of the hydrogen atoms of the alkene issubstituted with an alkyl or aryl. In particular embodiments, the alkeneis ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene,4-methyl-1-pentene, norbornene, 1-decene, butadiene, 1,5-hexadiene,styrene or a combination thereof.

The amount of the polyolefins in the polymer blend to make fibers can befrom about 0.5 to about 99 wt %, from about 10 to about 90 wt %, fromabout 20 to about 80 wt %, from about 30 to about 70 wt %, from about 5to about 50 wt %, from about 50 to about 95 wt %, from about 10 to about50 wt %, or from about 50 to about 90 wt % of the total weight of thepolymer blend.

Any polyolefin known to a person of ordinary skill in the art may beused to prepare the polymer blend disclosed herein. The polyolefins canbe olefin homopolymers, olefin copolymers, olefin terpolymers, olefinquaterpolymers and the like, and combinations thereof.

In some embodiments, one of the at least two polyolefins is an olefinhomopolymer. The olefin homopolymer can be derived from one olefin. Anyolefin homopolymer known to a person of ordinary skill in the art may beused. Non-limiting examples of olefin homopolymers include polyethylene(e.g., ultralow, low, linear low, medium, high and ultrahigh densitypolyethylene), polypropylene, polybutylene (e.g., polybutene-1),polypentene-1, polyhexene-1, polyoctene-1, polydecene-1,poly-3-methylbutene-1, poly-4-methylpentene-1, polyisoprene,polybutadiene, poly-1,5-hexadiene.

In further embodiments, the polyolefin is a propylene based polymer. Anypropylene based polymer known to a person of ordinary skill in the artmay be used to prepare the polymer blends disclosed herein. Non-limitingexamples of propylene based polymers include polypropylene (LDPP), highdensity polypropylene (HDPP), high melt strength polypropylene (HMS-PP),high impact polypropylene (HIPP), isotacetic polypropylene (iPP),syndiotacetic polypropylene (sPP) and the like, and combinationsthereof.

The amount of the propylene based polymer in the polymer blend can befrom about 0.5 to about 99 wt %, from about 10 to about 90 wt %, fromabout 20 to about 80 wt %, from about 30 to about 70 wt %, from about 5to about 50 wt %, from about 2.5 to about 20 wt %, from about 5 to about15 wt %, from about 50 to about 95 wt %, from about 10 to about 50 wt %,or from about 50 to about 90 wt % of the total weight of the polymerblend.

Crosslinking

The fibers can be cross-linked by any means known in the art, including,but not limited to, electron-beam irradiation, beta irradiation, gammairradiation, corona irradiation, silanes, peroxides, allyl compounds andUV radiation with or without crosslinking catalyst. U.S. Pat. Nos.6,803,014 and 6,667,351 disclose electron-beam irradiation methods thatcan be used in embodiments of the invention.

Irradiation may be accomplished by the use of high energy, ionizingelectrons, ultra violet rays, X-rays, gamma rays, beta particles and thelike and combination thereof. Preferably, electrons are employed up to70 megarads dosages. The irradiation source can be any electron beamgenerator operating in a range of about 150 kilovolts to about 6megavolts with a power output capable of supplying the desired dosage.The voltage can be adjusted to appropriate levels which may be, forexample, 100,000, 300,000, 1,000,000 or 2,000,000 or 3,000,000 or6,000,000 or higher or lower. Many other apparati for irradiatingpolymeric materials are known in the art. The irradiation is usuallycarried out at a dosage between about 3 megarads to about 35 megarads,preferably between about 8 to about 20 megarads. Further, theirradiation can be carried out conveniently at room temperature,although higher and lower temperatures, for example 0° C. to about 60°C., may also be employed. Preferably, the irradiation is carried outafter shaping or fabrication of the article. Also, in a preferredembodiment, the fibers which have been incorporated with a pro-radadditive is irradiated with electron beam radiation at about 8 to about20 megarads.

Crosslinking can be promoted with a crosslinking catalyst, and anycatalyst that will provide this function can be used. Suitable catalystsgenerally include organic bases, carboxylic acids, and organometalliccompounds including organic titanates and complexes or carboxylates oflead, cobalt, iron, nickel, zinc and tin. Dibutyltindilaurate,dioctyltinmaleate, dibutyltindiacetate, dibutyltindioctoate, stannousacetate, stannous octoate, lead naphthenate, zinc caprylate, cobaltnaphthenate; and the like. Tin carboxylate, especiallydibutyltindilaurate and dioctyltinmaleate, are particularly effective.The catalyst (or mixture of catalysts) is present in a catalytic amount,typically between about 0.015 and about 0.035 phr.

Representative pro-rad additives include, but are not limited to, azocompounds, organic peroxides and polyfunctional vinyl or allyl compoundssuch as, for example, triallyl cyanurate, triallyl isocyanurate,pentaerthritol tetramethacrylate, glutaraldehyde, ethylene glycoldimethacrylate, diallyl maleate, dipropargyl maleate, dipropargylmonoallyl cyanurate, dicumyl peroxide, di-tert-butyl peroxide, t-butylperbenzoate, benzoyl peroxide, cumene hydroperoxide, t-butyl peroctoate,methyl ethyl ketone peroxide, 2,5-dimethyl-2,5-di(t-butyl peroxy)hexane,lauryl peroxide, tert-butyl peracetate, azobisisobutyl nitrite and thelike and combination thereof. Preferred pro-rad additives for use insome embodiments of the invention are compounds which havepoly-functional (i.e. at least two) moieties such as C═C, C═N or C═O.

At least one pro-rad additive can be introduced to the polymer by anymethod known in the art. However, preferably the pro-rad additive(s) isintroduced via a masterbatch concentrate comprising the same ordifferent base resin as the ethylene interpolymer. Preferably, thepro-rad additive concentration for the masterbatch is relatively highe.g., about 25 weight percent (based on the total weight of theconcentrate).

The at least one pro-rad additive is introduced to the polymer in anyeffective amount. Preferably, the at least one pro-rad additiveintroduction amount is from about 0.001 to about 5 weight percent, morepreferably from about 0.005 to about 2.5 weight percent and mostpreferably from about 0.015 to about 1 weight percent (based on thetotal weight of the blend).

In addition to electron-beam irradiation, crosslinking can also beeffected by UV irradiation. U.S. Pat. No. 6,709,742 discloses across-linking method by UV irradiation which can be used in embodimentsof the invention. The method comprises mixing a photoinitiator, with orwithout a photocrosslinker, with a polymer before, during, or after afiber is formed and then exposing the fiber with the photoinitiator tosufficient UV radiation to crosslink the polymer to the desired level.The photoinitiators used in the practice of the invention are aromaticketones, e.g., benzophenones or monoacetals of 1,2-diketones. Theprimary photoreaction of the monacetals is the homolytic cleavage of theα-bond to give acyl and dialkoxyalkyl radicals. This type of α-cleavageis known as a Norrish Type I reaction which is more fully described inW. Horspool and D. Armesto, Organic Photochemistry: A ComprehensiveTreatment, Ellis Horwood Limited, Chichester, England, 1992; J. Kopecky,Organic Photochemistry: A Visual Approach, VCH Publishers, Inc., NewYork, N.Y. 1992; N. J. Turro, et al., Acc. Chem. Res., 1972, 5, 92; andJ. T. Banks, et al., J. Am. Chem. Soc., 1993, 115, 2473. The synthesisof monoacetals of aromatic 1,2 diketones, Ar—CO—C(OR)₂—Ar′ is describedin U.S. Pat. No. 4,190,602 and Ger. Offen. 2,337,813. The preferredcompound from this class is 2,2-dimethoxy-2-phenylacetophenone,C₆H₅—CO—C(OCH₃)₂—C₆H₅, which is commercially available from Ciba-Geigyas Irgacure 651. Examples of other aromatic ketones useful asphotoinitiators are Irgacure 184, 369, 819, 907 and 2959, all availablefrom Ciba-Geigy.

In one embodiment of the invention, the photoinitiator is used incombination with a photocrosslinker. Any photocrosslinker that will uponthe generation of free radicals, link two or more olefin polymerbackbones together through the formation of covalent bonds with thebackbones can be used. Preferably, these photocrosslinkers arepolyfunctional, i.e., they comprise two or more sites that uponactivation will form a covalent bond with a site on the backbone of thecopolymer. Representative photocrosslinkers include, but are not limitedto polyfunctional vinyl or allyl compounds such as, for example,triallyl cyanurate, triallyl isocyanurate, pentaerthritoltetramethacrylate, ethylene glycol dimethacrylate, diallyl maleate,dipropargyl maleate, dipropargyl monoallyl cyanurate and the like.Preferred photocrosslinkers for use in some embodiments of the inventionare compounds which have polyfunctional (i.e. at least two) moieties.Particularly preferred photocrosslinkers are triallycyanurate (TAC) andtriallylisocyanurate (TAIC).

Certain compounds act as both a photoinitiator and a photocrosslinker.These compounds are characterized by the ability to generate two or morereactive species (e.g., free radicals, carbenes, nitrenes, etc.) uponexposure to UV-light and to subsequently covalently bond with twopolymer chains. Any compound that can perform these two functions can beused in some embodiments of the invention, and representative compoundsinclude the sulfonyl azides described in U.S. Pat. Nos. 6,211,302 and6,284,842.

In another embodiment of this invention, the copolymer is subjected tosecondary crosslinking, i.e., crosslinking other than and in addition tophotocrosslinking. In this embodiment, the photoinitiator is used eitherin combination with a nonphotocrosslinker, e.g., a silane, or thecopolymer is subjected to a secondary crosslinking procedure, e.g.,exposure to E-beam radiation. Representative examples of silanecrosslinkers are described in U.S. Pat. No. 5,824,718, and crosslinkingthrough exposure to E-beam radiation is described in U.S. Pat. Nos.5,525,257 and 5,324,576. The use of a photocrosslinker in thisembodiment is optional.

At least one photoadditive, i.e., photoinitiator and optionalphotocrosslinker, can be introduced to the copolymer by any method knownin the art. However, preferably the photoadditive(s) is (are) introducedvia a masterbatch concentrate comprising the same or different baseresin as the copolymer. Preferably, the photoadditive concentration forthe masterbatch is relatively high e.g., about 25 weight percent (basedon the total weight of the concentrate).

The at least one photoadditive is introduced to the copolymer in anyeffective amount. Preferably, the at least one photoadditiveintroduction amount is from about 0.001 to about 5, more preferably fromabout 0.005 to about 2.5 and most preferably from about 0.015 to about1, wt % (based on the total weight of the copolymer).

The photoinitiator(s) and optional photocrosslinker(s) can be addedduring different stages of the fiber or film manufacturing process. Ifphotoadditives can withstand the extrusion temperature, an olefinpolymer resin can be mixed with additives before being fed into theextruder, e.g., via a masterbatch addition. Alternatively, additives canbe introduced into the extruder just prior the slot die, but in thiscase the efficient mixing of components before extrusion is important.In another approach, olefin polymer fibers can be drawn withoutphotoadditives, and a photoinitiator and/or photocrosslinker can beapplied to the extruded fiber via a kiss-roll, spray, dipping into asolution with additives, or by using other industrial methods forpost-treatment. The resulting fiber with photoadditive(s) is then curedvia electromagnetic radiation in a continuous or batch process. Thephoto additives can be blended with an olefin polymer using conventionalcompounding equipment, including single and twin-screw extruders.

The power of the electromagnetic radiation and the irradiation time arechosen so as to allow efficient crosslinking without polymer degradationand/or dimensional defects. The preferred process is described in EP 0490 854 B1. Photoadditive(s) with sufficient thermal stability is (are)premixed with an olefin polymer resin, extruded into a fiber, andirradiated in a continuous process using one energy source or severalunits linked in a series. There are several advantages to using acontinuous process compared with a batch process to cure a fiber orsheet of a knitted fabric which are collected onto a spool.

Irradiation may be accomplished by the use of UV-radiation. Preferably,UV-radiation is employed up to the intensity of 100 J/cm². Theirradiation source can be any UV-light generator operating in a range ofabout 50 watts to about 25000 watts with a power output capable ofsupplying the desired dosage. The wattage can be adjusted to appropriatelevels which may be, for example, 1000 watts or 4800 watts or 6000 wattsor higher or lower. Many other apparati for UV-irradiating polymericmaterials are known in the art. The irradiation is usually carried outat a dosage between about 3 J/cm² to about 500 J/scm², preferablybetween about 5 J/cm² to about 100 J/cm². Further, the irradiation canbe carried out conveniently at room temperature, although higher andlower temperatures, for example 0° C. to about 60° C., may also beemployed. The photocrosslinking process is faster at highertemperatures. Preferably, the irradiation is carried out after shapingor fabrication of the article. In a preferred embodiment, the copolymerwhich has been incorporated with a photoadditive is irradiated withUV-radiation at about 10 J/cm² to about 50 J/cm².

Other Additives

Antioxidants, e.g., Irgafos 168, Irganox 1010, Irganox 3790, andChimassorb 944 made by Ciba Geigy Corp., may be added to the ethylenepolymer to protect against undo degradation during shaping orfabrication operation and/or to better control the extent of grafting orcrosslinking (i.e., inhibit excessive gelation). In-process additives,e.g. calcium stearate, water, fluoropolymers, etc., may also be used forpurposes such as for the deactivation of residual catalyst and/orimproved processability. Tinuvin 770 (from Ciba-Geigy) can be used as alight stabilizer.

The copolymer can be filled or unfilled. If filled, then the amount offiller present should not exceed an amount that would adversely affecteither heat-resistance or elasticity at an elevated temperature. Ifpresent, typically the amount of filler is between 0.01 and 80 wt %based on the total weight of the copolymer (or if a blend of a copolymerand one or more other polymers, then the total weight of the blend).Representative fillers include kaolin clay, magnesium hydroxide, zincoxide, silica and calcium carbonate. In a preferred embodiment, in whicha filler is present, the filler is coated with a material that willprevent or retard any tendency that the filler might otherwise have tointerfere with the crosslinking reactions. Stearic acid is illustrativeof such a filler coating.

To reduce the friction coefficient of the fibers, various spin finishformulations can be used, such as metallic soaps dispersed in textileoils (see for example U.S. Pat. No. 3,039,895 or U.S. Pat. No.6,652,599), surfactants in a base oil (see for example US publication2003/0024052) and polyalkylsiloxanes (see for example U.S. Pat. No.3,296,063 or U.S. Pat. No. 4,999,120). U.S. patent application Ser. No.10/933,721 (published as US20050142360) discloses spin finishcompositions that can also be used.

The following examples are presented to exemplify embodiments of theinvention but are not intended to limit the invention to the specificembodiments set forth. Unless indicated to the contrary, all parts andpercentages are by weight. All numerical values are approximate. Whennumerical ranges are given, it should be understood that embodimentsoutside the stated ranges may still fall within the scope of theinvention. Specific details described in each example should not beconstrued as necessary features of the invention.

EXAMPLES

Fibers

Polymer samples from Example 1, Example 17 and Comparative G are spuninto a multifilament bundle of 24 fibers with round cross-sections in afiber spinning line (Foume) equipped with twenty four 25×1 mmspinnerets, a spin head temperature of 260° C., a melt temperature of302° C. and a winder speed of 70 m/min. Other spinning conditions arelisted in Table 10. The denier of the resulting bundle is approximately95 to 100 denier (g/9000 m). TABLE 10 Pump Size (cm³/rev) 1.12 PumpSpeed (rpm) 10 Screen Size, mesh (μm) 325 (45) Extruder DischargePressure (MPa) 2

The fibers are crosslinked by passing six times through an electronbeaming crosslinking machine operating at an electron beam dosage of 32KGy/pass, giving a total dosage level of 192 KGy. Between each pass, thefibers are cooled to −10° C.

The tensile behavior of the resulting uncrosslinked and crosslinkedfibers is measured according to BISFA Test Methods for Bare ElasticYarns, Chapter 6: Tensile Properties using Option C clamps and Option Atest speed. Tenacity and elongation at break are reported from anaverage of 5 replications. The recovery behavior of the crosslinkedfibers is also measured using BISFA Test Methods for Bare Elastic Yarns,Chapter 7: Viscoelastic Properties Procedure A where the fiber iscyclically loaded to 300 percent strain. The percent permanentdeformation is calculated at the beginning of the 6^(th) cycle asspecified in the test method.

Stress relaxation of crosslinked fibers is measured from 10 percentstrain at alternating temperatures of 21° C. and 40° C. In theexperiment, 13 loops of the bundle fibers with a circumference of 324 mmare mounted to an Instron test machine by 2 hooks resulting in a gaugelength of 162 mm. The sample is stretched to 10 percent strain at a rateof 100 percent elongation/minute at 21° C. and then held for 10 minutes.The subsequent thermal treatment is: 10 minutes at 40° C. in a waterbath, 10 minutes at 21° C. in air, 10 minutes at 40° C. in a water bath,and 10 minutes at 21° C. in air. The time to transfer the sample betweenthe water bath and the air cooling chamber is 6 seconds. During theentire process, the load is monitored. The percent load change from theload at 35 minutes and the load at 45 minutes is calculated using theformula:${\%\quad{load}\quad{change}} = \frac{{L\left( {t = {35\quad\min}} \right)} - {L\left( {t = {45\quad\min}} \right)}}{L\left( {t = {35\quad\min}} \right)}$

where L(t=35 min) and L(t=45 min) are loads at 35 minutes and 45minutes, corresponding to the middle periods of the last 40° C. waterbath and 21° C. air exposures, respectively. Fiber properties are alsotabulated in Table 11. TABLE 11 Fiber Properties UncrosslinkedCrosslinked Tena- Tena- Permanent city Elongation city ElongationDeforma- Percent (gf/ at Break (gf/ at Break tion Load Ex. denier)(percent) denier) (percent) (percent) Change 11 3.7 720 5.0 669 133 4 G*6.4 423 7.7 382 137 25

In fibers prepared from both polymer Example 11 and Comparative G,crosslinking results in an increase in tenacity with some loss ofelongation. Both examples show similar permanent deformation ofapproximately 135 percent. Example 11 displays lower stress relaxationthan Comparative G as well as being less temperature sensitive. Thepercent load change between 40° C. (35 min) and 21° C. (35 min) arelisted in Table 9. The fiber prepared from Example 11 polymer shows only4 percent change in load whereas the fiber of Comparative G displays 25percent change. Low temperature sensitivity in stress relaxation isimportant in maintaining long shelf life of fiber bobbins. Hightemperature sensitivity in stress relaxation can lead to bobbin defectsduring storage in a non-climate controlled storage facility as the fiberalternately relaxes and constricts due to temperature fluctuations. Thiscan lead to problems such as poor fiber unwinding behavior and fiberbreaks in subsequent downstream processing of the fiber.

Fiber Production

Monofilament fibers of 40 denier are melt spun into 100 to 300 g bobbinsusing inventive Ex. 19A and Ex. 19B, and comparative Ex. 19K (AFFINITY®EG8100 (The Dow Chemical Company)) with a 2.7×0.9 mm round spinneret.With density and melt index similar to Ex. 19A and Ex. 19B, Ex. 19K isan ethylene-octene copolymer with 0.870 g/cc density as determined byASTM D-792 and 1 MI as determined according to ASTM D-1238, Condition190° C./2.16 kg. Spinning temperatures range from 280° C. to 290° C. forEx. 19A and Ex. 19B. Ex. 19K is spun at 290° C. and 300° C. only due toexcessive fiber breakage when spun at a lower temperature. Between thespinneret and the take-up roller, there is a cold air quench chamberwith 2 m in length for solidifying the fiber. A silicone based spinfinish of Lurol 8517 (Goulston Technologies) is applied at 2 wt % to thesurface of the fiber via a spin finish applicator after the fiber hadsolidified from the melt. Afterwards, the fiber is wound into a bobbinwith speeds ranged from 400 to 600 m/min. The spinning temperature andwinding speeds are processing variables used to tailor the tensileresponse of the resulting fiber. Prior to spinning, resins from each ofthe examples are compounded with 3000 ppm of Cyanox 1790 (CytecIndustries) and 3000 ppm of Chimasorb 944 (Ciba Specialty Chemicals) asantioxidants.

Example 1 Mechanical Properties

The tensile behaviors of fibers spun from Ex. 19A, Ex. 19B, and Ex. 19Kare measured based on BISFA Test Methods for Bare Elastic Yarns, Chapter6: Tensile

Properties Option A. F Fibers are tested at 500 mm/min with 100 mm gaugelength. Pneumatic clamps are used (Model 2712-001, Instron Corp.).Tenacity, elongation at break, and load at 300% elongation are reportedfrom an average of 5 replicates.

The recovery behavior of fibers are also measured using BISFA TestMethods for Bare Elastic Yarns, Chapter 7: Viscoelastic PropertiesProcedure A where the fiber is cyclically loaded to 300% strain. The %permanent deformation is calculated after the 1^(st) and 5^(th) cycle inthe loading curve as specified in the test method. As comparison, acommercial crosslinked 40 denier XLA® Fiber (The Dow Chemical Company)is also measured for tensile and recovery behaviors.

Mechanical properties of fibers spun from Ex. 19A, Ex. 19B, ComparativeEx. 19K, and Comparative Ex 19L which is a commercial product of 40denier XLA® fibers (The Dow Chemical Company) are shown in Table 12. Thespinning conditions for Ex. 19A, Ex. 19B, and Ex. 19K are chosen suchthat the elongation at break is comparable to the commercial product inEx. 19L. The data show that Ex. 19A and Ex. 19B needs to be spun atlower temperatures and higher speeds than Ex. 19K and Ex. 19L in orderto achieve similar elongation at break. This suggests that one canpotentially increase production throughput when using the inventiveexamples.

Often, higher tension is desired for downstream fiber processing. Inapplications where fiber is unwound positively (unwind under constantdraw ratio), the line tension can drop as the fiber passes throughvarious guides and elements due to friction. Fiber can break in themachine if the line tension is dropped too low. Table 12 shows that Ex.19A and Ex 19B had higher loads that Ex. 19K and Ex. 19L at 300% strainwhile maintaining similar elongation at break. In particular, Ex. 19Aexhibits significantly higher load at 300% (10.2 g for Ex. 19A versus7.0 g for Ex. 19L)

For elastic fibers, high degree of recovery is preferred afterstretching. Both Ex 19A and Ex 19B show lower permanent set (higherrecovery) than comparative Ex 19K. and Ex. 19L, with Ex. 19B showingsignificantly lower permanent set (48% after 5 cycles for Ex 19B versus117% for Ex. 19L).

For some of the elastic fibers according to embodiments of theinvention, inventive block interpolymers having a higher Mw/Mn, e.g.,greater than about 2.5, and as high as about 5, preferably as high asabout 4, are preferred for lower permanent set than fibers made frominventive block interpolymers having Mw/Mn less than about 2.5. Thepermanent set at 300% elongation after one hysteresis cycle of thesefibers made from the higher Mw/Mn polymers is no more than 60%,preferably no more than about 50%, more preferably no more than about40%, and can be as low as 0%. It was observed that diethyl zinc, used asthe shuttling agent, correlates with Mw/Mn, such that higher diethylzinc levels used to polymerize the multi-block polymers result innarrower Mw/Mn and higher permanent set.

Example 2 Dynamic Friction with Ceramic and Metal Pins

Frictional property is measured using Electronic Constant TensionTransporter, or ECTT (Lawson Hemphill). A schematic of the setup isshown in FIG. 10. The ECTT consists of a feed roll (1) and a take-uproll (2) controlled independently by a computer (not shown). Fiber isfed at constant tension using a feeder attachment (3) (Model KTF 100HP,BTSR) and it is wound up at the other end at 100 m/min. Tensions beforeand after a friction pin (4) are measured with two 25 cN load cell(Perma Tens 100p/100cN, Rothschild). Between the load cells, the fiberpasses across a 6.4 mm diameter friction pin at 90° wrap angle. Twodifferent friction pins are used to simulate the range of surfaces afiber can encounter during post-spinning processing. The first type is aceramic pin (R.250S P2, Heany Industries) with a surface roughness of0.32 μm Ra. The second type of pin is considerably smoother with Ra of0.14 μm made from nickel plated polished steel. The fiction coefficientcan be calculated using the Euler formula:$\frac{T_{2}}{T_{1}} = {\mathbb{e}}^{\mu\quad\theta}$where μ is the friction coefficient, T₂ is the tension after the pin, T₁is the tension before the pin, and θ is the wrap angle (π/2).

Dynamic coefficient of friction (COF) results are listed in Table 13.The data show that inventive Ex. 19A. and Ex. 19B have lower frictionthan Ex. 19K and Ex. 19L in ceramic and steel pins. Having low COF isdesirable because high friction can often lead to fiber breaks inweaving and knitting applications. For some preferred fibers of theinvention, the COF with polished metal can be relatively low, as low asabout 1.15 and less, preferably 1.1 or less, more preferably 1 or less,and as low as about 0.8. The date of Table 13 shows that fibers of theinvention have lower COF than comparative fibers, even though all of thefibers have the same amount and type of spin finish.

Example 3 Crosslinking

After spinning, fibers are packaged under nitrogen and crosslinkedthrough electron beaming (e-beam) to impart high temperature resistance.Spun fibers are irradiated with a dosage of 192 KGy using a series of 6passes through the e-beam line (Ionmed, Spain) with a dosage of 32 KGyfor each pass. Between each pass, the fibers are cooled to −10° C. dueto heating during the e-beam process.

Dynamic mechanical spectroscopy (DMS) is performed on an RSA IIIextensional rheometer (TA instruments) to measure heat resistance. Abundle of 60 40-denier fibers is clamped at both ends between fixturesseparated by 10 mm. The sample is then subjected to successivetemperature steps from 25° C. to 200° C. at 3° C. per step. At eachtemperature, the storage modulus, E′, is measured at a strain frequencyof 10 rad/s and a strain amplitude cycling between 0.1% and 5%. Aninitial static force of 5 g is applied to prevent slack in the sample.The test ends when the temperature reaches 200° C.

FIG. 11 shows the dynamic mechanical thermal response of crosslinked Ex.19A, Ex 19B, Ex 19K and Ex 19L. The plot shows that Ex. 19A and Ex 19Bhave 10 times higher modulus than Ex 19L between 75° C. and 110° C. Thestorage modulus ratio of E′(25° C.)/E′(100° C.) are listed in Table 14.The fibers from inventive polymers have a storage modulus ratio of 3 orless, whereas comparative examples have a storage modulus ratio of 10and above. It is desirable that the storage modulus ratio of the fiberbe as close to 1 as possible. Such fibers will be relatively lessaffected by temperature and can provide performance advantages such asimproved tolerance to heat during storage and e-beaming.

Example 4 Unwind Behavior

An important performance property for elastic fibers is that the fiberneeds to be unwound from the bobbin smoothly and without breaks. Theunwind tension, its variation, and gradients of tension within thebobbin can be used to infer bobbin unwinding performance in yarn andtextile unit operations. The ECTT is used to measure end-on unwindtension at 200 m/min take-up speed, as shown in FIG. 12. Data aregathered for a period of 5 minutes with the last 3 minutes of the scanused to obtain the mean and the standard deviation of unwind tension.Bobbins of 300 g are used for the test with 2 storage conditions. Theyare either stored at 21° C. about 1 day after spinning or stored in anoven at 40° C. for 12 hours to simulate accelerated aging. Unwindtension measurements are taken at 3 positions of the spool: surface, 0.5cm where about half the fibers are stripped off, and 0.5 cm, where mostof the fibers are stripped off.

The results are shown in FIG. 13, where the unwind tension is plottedagainst spool size. FIG. 13 a shows that storage at 21° C. shows thatboth Ex. 19A and Ex 19L have unwind tensions relatively constant withspool size, with Ex. 19A showing higher tension at about 1.6 g versusabout 1.0 g for Ex. 19L. After subjected to storage at 40° C. for 12hours, the unwind tension for both examples increases but to a greaterextent for Ex. 19L (FIG. 13 b). The unwind tension for Ex 19A isrelatively constant with spool size at 2.0 to 2.3 g. For Ex. 19L, thesurface had an unwind tension of 1.4 g at the surface and increasessignificantly to almost 3.0 g at 1.5 cm spool size. Because of thehigher melting temperature in the inventive example, the unwindperformance is less temperature sensitive during storage and canpotentially have longer shelf life than the comparative example. TABLE12 Mechanical properties of fibers Spinning Conditions Elongation atBreak (%) Tenacity (g/denier) Load at 300% (g) Permanent Set (%) ExampleTemp. (° C.) Speed (m/min) Average Std Dev Average Std Dev Average StdDev 1 Cycle 5 Cycles 19A 290 500 534 22 1.0 0.1 10.2 0.2 64 93 19B 280500 540 10 1.0 0.0 8.3 0.4 38 48 19K 300 400 536 10 1.2 0.1 6.3 0.0 89103 19L 300 450 528 16 1.3 0.2 7.0 0.2 102 117

TABLE 13 Dynamic friction coefficients COF Example Ceramic Metal 19A0.63 1.09 19B 0.62 1.01 19K 0.81 1.21 19L 0.73 1.28

TABLE 14 Storage modulus ratios E′(25° C.)/E′(100° C.) Example E′(25°C.)/E′(100° C.) 19A 3 19B 2 19K 10 19L 14

Nonwoven Fabrics

The resins listed in the table below are used in following examples.Melt Density, Ex. Resin Grade Flow g/cc Note 19C Inventive 5 MI 0.877polymer 19E Inventive 5 MI 0.877 polymer 19D Inventive 5 MI 0.877polymer 19J Inventive 5.5 MI 0.900 polymer 19I Inventive 10 MI 0.877polymer 19M AFFINITY ® EG8200G 5 MI 0.870 19N AFFINITY ® 10 MI 0.870 19OVERSIFY ® DE4300 25 MFR 0.8665 equiv. to 8.3 MI* 19P VERSIFY ® DE3300 8MFR 0.8665 equiv. to 2.7 MI*

Spinning Conditions

Fiber samples are prepared by using the Hills Bi-component Fiber Line.The fiber spinning line consists of two 1″ single screw extruders, twoZenith gear pumps, a 144-hole spinneret with a blocking plate whichreduced the available holes to 72, a fiber quenching cabinet, and awind-up station. The capillary hole of the spinneret is 0.65 m indiameter with L/D ratio=3.85:1. The melt temperature is set to 245° C.The throughput is 0.6 grams per hole per minute (ghm). Fibers are spunby using two different methods, air drawing, and mechanical drawing byusing a winder to collect fiber packages for property testing.

Determination of Stickpoint

“Stickpoint” is defined as the point in the spinline at which the fiberis solid enough not to stick to an object. Stick points are usuallymeasured by stringing up the fiber at fixed speeds (e.g., 1000, 2000,3000 m/min), and then pressing a glass rod against the front of thefiber bundle at the bottom of the quench cabinet. The glass rod isslowly raised until the fiber sticks to the rod. The distance from thespinneret to the point in the cabinet where the glass rod stuck to thefibers is recorded as the stickpoint. This measurement is repeated 3times at each spinning speed and the stick points are averaged. Whenmeasuring the stick point or collecting the monocomponent elasticfibers, only the A-side extruder was used for extruding fibers

Aspirator/Moving Screen Setup for Roping Study

FIG. 14 is a schematic representation of a setup to simulate conditionsin a spunbond line in which roping could occur. It is an aspirator(3)/moving screen (4) setup constructed to air draw fibers (1A) throughthe aspirator (3). The fibers (1B) after passing through the aspirator(3) form a fiber web (2). This setup uses an aspirator (3) (AirAmplifier, model ITW Vortex 912/952 by Transvector Incoporation) with1.625 inch diameter opening. It is located at 60 inches (about 150 cm)below the die face (not shown) from which fibers (1B) exit. It alsoallows the aspirator (3) to be below the predicted stick point of thespinning line (estimated to be about 35 inches for the target denier).An inlet pressure of 100 psi for a 0.3 ghm throughput is used.

A manually moving screen and rack system (4) about 10 inches under theaspirator (3) is installed to continuously collect fiber webs (2). Thisis intended to simulate a wire or web former. In the aspirator (3), theconfined space and air turbulence are thought to generate a highprobability of fiber-fiber contacts. It is assumed that this gives theopportunity for fibers to block. Fibers (1B) that collide and do nothave significant adhesion have the opportunity to separate upondeceleration at the aspirator exit. In contrast, an adhesive bond ofsufficient strength may propagate as fiber is drawn through theaspirator (3). This is thought to produce a continuous bond along thefiber axis resulting in the structure known as a rope.

100% Hysteresis Test for Determining Immediate Set and Retained Load

The fiber strand comprising 72 filaments is prepared and gripped in theInstron with 3″ gauge length. The crosshead speed is set at 10 inchesper minute. The crosshead is raised until a strain of 100% is applied,and then the crosshead is returned at the same crosshead speed to 0%strain. After returning to 0% strain, the crosshead is extended at 10inches per minute to 100% strain as calculated for the original 3 inchlength. The onset of load was taken as the immediate set.

Reduced load is measured during the first extension and first retractionof the sample at 30% strain. Retained load is calculated as the reducedload at 30% strain during the first retraction divided by the reducedload at 30% strain during the first extension and then multiplied by100.

Stickpoint Measurement

Stickpoint represents the melt freezing point formed understress-induced/enhanced crystallization during drawing. Lower stickpoint(closer to the die) is desired to avoid roping. TABLE 15 Stickpoints forVarious Fibers Ex Stickpoint, cm 19I 42 19N 53 19O 62

TABLE 16 Visual Ranking of Comparable Web Formations Visual Web SamplesFormation Ranking 19I A 19N C 19O B

In the visual ranking test on web formations, A is the best with leastroping, while C is the worst with most roping. FIG. 15 is a photo of thethree webs for Ex. 19I, Ex 19N, and Ex 19O.

Thus, non-woven fabrics comprising fibers made from the inventive blockcopolymers or interpolymers will have a lesser degree of roping thannon-woven fabrics (e.g., spunbond or melt blown) made from fiberscomprising a similar random copolymer. By similar, it is meant that themelt index, and density are within 10% of each other, and that eachcopolymer comprises the same monomers. By improved roping, it is meantthat there are a minimal number of filament/fiber aggregates (bundles).Filament aggregates consist of multiple filaments in parallelorientation fused together. To quantify a fabric with good formation(i.e., minimal roping), the number of filament aggregates per 2 cmlength is measured. Each filament aggregate is at least 10 times thefiber width in length. Care is taken not to include thermal and pressurebond points in the 2 cm length. The linear line count of filamentaggregates is taken over a 2 cm length in random directions. For goodweb formation, the number of filament aggregates is lower than 30/2 cm,preferentially lower than 20/2 cm, and can be as low as about 5/2 cm,preferably as low as about 1/2 cm, especially as low as 0/2 cm (i.e.,rope free).

Immediate Set and Retained Load

FIG. 16 shows that the fibers made in accordance with embodiments of theinvention can also exhibit low immediate set, after testing at onehysteresis cycle at 100% strain. The immediate set can be as low as 20%,preferably as low as about 10% and can be as low as 0% immediate set,especially for fibers made from inventive block copolymers orinterpolymers having densities of about 0.9 g/cm³ or less, preferablyabout 0.895 g/cm³ or less, more preferably 0.89 g/cm³ or less, and canbe as low as about 0.85 g/cm³.

It is seen from FIG. 17 that fibers made from inventive polymers havelower immediate set than AFFINITY® and VERSIFY® fibers. Higher densityfiber shows higher immediate set, as expected. At 60% strain, inventivefibers show higher retained load than AFFINITY® and VERSIFY® asdemonstrated in FIG. 17 and Table 17. This is because inventive fibershave lower extension forces. TABLE 17 Immediate Set and Retained Loadfor Comparable Fibers Spinning Speed, Immediate Set, Retained Ex Resinsm/min % Load, % 19C Inventive Polymer 750 8 14.6 19C Inventive Polymer1000 10 12.1 19E Inventive Polymer 750 12 13.5 19E Inventive Polymer1000 17 12.1 19D Inventive Polymer 750 15 10.7 19D Inventive Polymer1000 20 8.1 19M AFFINITY ® 750 20 6.0 EG8200G 19M AFFINITY ® 1000 23.25.4 EG8200G 19P VERSIFY ® 750 21 6.1 DE3300 19P VERSIFY ® 1000 26 5.5DE3300

Additional Examples Polymer Example 20

Continuous solution polymerizations are carried out in a computercontrolled well-mixed reactor. Purified mixed alkanes solvent (Isopar™ Eavailable from Exxon Mobil, Inc.), ethylene, 1-octene, and hydrogen(where used) are combined and fed to a 40 gallon reactor. The feeds tothe reactor are measured by mass-flow controllers. The temperature ofthe feed stream is controlled by use of a glycol cooled heat exchangerbefore entering the reactor. The catalyst component solutions aremetered using pumps and mass flow meters. The reactor is run liquid-fullat approximately 725 psig pressure. Upon exiting the reactor, water andadditive are injected in the polymer solution. The water hydrolyzes thecatalysts, and terminates the polymerization reactions. The post reactorsolution is then heated in preparation for a two-stage devolatization.The solvent and unreacted monomers are removed during the devolatizationprocess. The polymer melt is pumped to a die for underwater pelletcutting. The reactor conditions are shown in Table 18.

The prime product was collected under stable reactor conditions. Afterseveral hours, the product samples showed no substantial change in meltindex or density. The products were stabilized with a mixture ofIRGANOX®1010, IRGANOX® 1076 and IRGAFOS® 176. TABLE 18 Cat A1² Cat A1Cat B2³ Cat B2 DEZ DEZ C₂H₄ C₈H₁₆ Solv. H₂ Conc. Flow Conc. Flow ConcFlow Ex. lb/hr lb/hr lb/hr sccm¹ T° C. ppm lb/hr ppm lb/hr wt % lb/hr 21130.7 196 713 1767 120 500 1.06 299 0.57 4.81 0.48 [DEZ]⁴ Cocat 1 Cocat1 Cocat 2 Cocat 2 in Poly Conc. Flow Conc. Flow polymer Rate⁵ Conv.⁶Polymer Ex. ppm lb/hr ppm lb/hr ppm lb/hr wt % wt % Eff.⁷ 21 5634 1.24402 0.478 131 177 89 16.94 252¹standard cm³/min²[N-(2,6-di(1-methylethyl)phenyl)amido)(2-isopropylphenyl)(α-naphthalen-2-diyl(6-pyridin-2-diyl)methane)]hafniumdimethyl³bis-(1-(2-methylcyclohexyl)ethyl)(2-oxoyl-3,5-di(t-butyl)phenyl)immino)zirconiumdibenzyl⁴ppm in final product calculated by mass balance⁵polymer production rate⁶weight percent ethylene conversion in reactor⁷efficiency, kg polymer/g M where g M = g Hf + g Z

The structures for the two catalysts used in the above procedures (i.e.,Catalysts A1 and A2) are shown below:

Polymer Example 20 is an ethylene/1-octene block copolymer having acomposite 1-octene content of 11.1 mol % (33 wt. %), a composite densityof 0.880 g/cc, a DSC peak melting point of 123° C., a hard segment levelbased upon DSC measurement of 0.4 mol % (1.6 wt. %), an ATREFcrystallization temperature of 91° C., a number average molecular weightof 43,600 g/mol, a weight average molecular weight of 119,900 g/mol, anda melt index at 190° C., 2.16 Kg of about 1 dg/min.

Fibers 1, 2 and 3 are made from Polymer Example 20 at 40d, 70d and 140d,respectively. Monofilament fibers are melt spun into 100 to 300 gbobbins with a 0.8 mm round spinneret at a spinning temperature of about300° C. Between the spinneret and the takeup roller, there is a cold airquench chamber with 2 m in length for solidifying the fiber. A siliconebased spin finish of Lurol 8517 (Goulston Technologies) is applied at 2wt % to the surface of the fiber via a spin finish applicator after thefiber solidifies from the melt. Afterwards, the fiber is wound into abobbin with speeds ranging from 400 to 600 m/min. The spinningtemperature and winding speeds are processing variables used to tailorthe tensile response of the resulting fiber. Prior to spinning, resinsfrom each of the examples are compounded with 3000 ppm of Cyanox 1790(Cytec Industries) and 3000 ppm of Chimasorb 944 (Ciba SpecialtyChemicals) as antioxidants.

Fibers from Blends of Polymer Example 20 and Polypropylene

PP 1 is a polypropylene homopolymer having a melt flow index at 230° C.,2.16 Kg of 38 dg/min, a DSC melting point of 164° C., and a density of0.90 g/cc.

PP2 is a polypropylene homopolymer having a melt flow index at 230° C.,2.16 Kg of 9.5 dg/min, a DSC melting point of 164° C., and a density of0.90 g/cc.

PP3 is a polypropylene homopolymer having a melt flow index at 230° C.,2.16 Kg of 8.0 dg/min, a DSC melting point of 166° C., and a density of0.90 g/cc.

PP4 is a polypropylene homopolymer having a melt flow index at 230° C.,2.16 Kg of 35 dg/min, a DSC melting point of 166° C., and a density of0.90 g/cc.

Fibers are spun from various blends of Polymer Example 20 andpolypropylene as indicated in Tables 19-21. TABLE 19 40 d fibers FiberParts Ex. 20 Polymer Parts PP 4 90 10 PP1 5 90 10 PP2

TABLE 20 70 d fibers Fiber Parts Ex. 20 Polymer Parts PP 6 90 10 PP3 790 10 PP4 8 85 15 PP4

TABLE 21 140d fibers Fiber Parts Ex. 20 Polymer Parts PP 9 90 10 PP3 1090 10 PP3Fiber Properties for Polymer Example 20 and Blends thereof withPolypropylene

The formulations listed in Tables 19-21 are melt-blended by using atwin-screw extruder before fiber spinning. The blends are tumble mixedbefore compounding. The melt blending is conducted on a ZSK-25 (25 mm)counter-rotating twin extruder using a standard screw design suitablefor compounding polypropylene blends, under the following conditions:length to diameter ratio (L/D) for the screw=35, die temperature=235°C., screw speed=300 rpm, and torque level=65 to 70%.

Fibers 4 and 5 are spun using a 0.8 mm round profile die at about 30° C.Fibers 6-8 are spun using a 0.8 mm round profile die at about 290° C.Fibers 9 and 10 are spun using a 5:1 rectangular die at 290° C.Additional conditions are listed below in Table 22. TABLE 22 Pump Size(cm³/rev) 1.12 Pump Speed (rpm) 10 Screen Size, mesh (μm) 325 (45)Extruder Discharge Pressure (MPa) 2

Fibers 1, 4 and 5 are crosslinked by passing six times through anelectron beaming crosslinking machine giving a total dosage level of 176KGy. Between each pass, the fibers are cooled to −10° C. The crosslinkedfibers will be referred to as Fiber 1 CL, Fiber 4 CL and Fiber 5 CLrespectively.

Gel Content

The percent gel content of the crosslinked fibers is measured by thexylene extraction method according to ASTM D2765-95a, which is hereinincorporated by reference. The blend fibers, Fibers 4 and 5, had lowergel contents than Fiber 1, as would be expected due to the dominantchain-scission responses of polypropylene under e-beaming. However, theblend of Fiber 4 showed a lower reduction of gel content as compared toFiber 1 than that of Fiber 5, and this gel reduction level is less thanthe physical blending ratio. This suggests that some portion of thepolypropylene may be crosslinked. The gel contents are shown in Table23. TABLE 23 Gel content for Fiber 1 CL, Fiber 4 CL and Fiber 5 CL. % wtGel Content difference % wt Gel Content from Fiber 1 Fiber 1 CL 63.3 —Fiber 4 CL 60.8 2.5 Fiber 5 CL 57.3 6.0Thermal Behavior

The thermal behavior of Fibers 1, 4 and 5 was studied via DSC. FIGS. 18and 19 show the heating and cooling behaviors respectively. In FIG. 18,the polypropylene melting peak at 164° C. was clearly preserved in theblend fiber. It is believed that the higher melting temperature of thepolypropylene will allow the blend fibers to show improved performancein the cone dyeing process with PET/cotton CSY, where the requireddyeing temperature is 130° C. In FIG. 19, it is seen that the originalpolypropylene crystallizing peak at 125° C. disappeared in the blendcooling process. Not wishing to be bound by any particular theory, it ispostulated that the effect of supercooling caused the crystallizationpeak of the polypropylene component to be lower in the blend.

Tensile Behavior

The tensile behavior of the uncrosslinked fibers is measured using anInstron Universal Tester (Instron, Corp.), at 508 mm/min with 102 mmgauge length. Pneumatic clamps are used (Model 2712-001, Instron Corp.)with a grip pressure of 60 psi (about 413 kPa). Tenacity, elongation atbreak, and load at 300% elongation are reported from an average of 5replicates. Tensile data at 23° C. is given in Tables 24-27. TABLE 24Tensile properties for uncrosslinked 40d blend fibers Fiber 1 Fiber 4Fiber 5 Load at 300% (g) 10.5 9.3 13.4 Elongation to break (%) 475 508458 Load at break (g) 40.1 39.1 39.8

TABLE 25 Tensile properties for uncrosslinked 70d blend fibers Fiber 2Fiber 6 Fiber 7 Fiber 8 Load at 300% (g) 6.8 10.6 9.7 11.3 Elongation tobreak (%) 614 606 598 532 Load at break (g) 51 63.3 59.6 50.8

TABLE 26 Tensile properties for uncrosslinked 140d fibers Fiber 3 Fiber9 Fiber 10 Load at 400% (g) 19.8 26.5 25.2 Elongation to break (%) 630637 635 Load at break (g) 97 127.4 114.3 Permanent Set w/300% strain 4464 —

The tensile test at elevated temperatures is carried out in an Instronin an environment chamber. Fibers are stretched to a given draft ratio(e.g., 3×) on a Teflon sheet, then heat treated at a predefinedtemperature (e.g., 95° C.) for 10 min to simulate the streaming process.A card board window (1 inch long) is then placed on the stretchedfibers. 3M Scotch tape is used to fix the fiber to the card board sothat fibers are not allowed to shrink in order to simulate the fiberstretching state in core spun yarn. The card board with fiber is thenclamped. Before the tensile stretching, the waist of the window is cutto allow fiber stretching. Fiber properties are tested at the conedyeing temperature (e.g., 95° C.). TABLE 27 High temperature tensileproperties of 40d fibers Fiber 1 Fiber 4 Fiber 5  95° C. Fracture load(g) 10.2 11.2 7.6  95° C. Elongation to break (%) 148 115 75 120° C.Fracture load (g) 5.7 7.7 6.3 120° C. Elongation to break (%) 102 113124Dynamic Friction with Metal Pins

The frictional property is measured using an Electronic Constant TensionTransporter or ECTT ST200 (Lawson Hemphill). A schematic of the setup isshown in FIG. 12. The ECTT ST200 consists of an elastomeric yarn feeder(EYF) (1) and a take-up roll (2) controlled independently by a computer(not shown). A draft of 1.5× was applied (ratio between take-up linealspeed and EYF lineal speed). This draft value is a reference obtainedfrom historic draft partitioning data coming from commercial warpingmachines. A piece of a commercial standard creel type 23E-1100 82 mmLIBA unwinding roll (LIBA Maschinenfabrik GmbH) is placed between theEYF and the take-up roll (friction element). Tensions are measured witha single 10 cN load cell (Perma Tens 100p/50cN, Rothschild).

Two configurations in ECTT are used to calculate the LIBA dynamic COF,under the same 1.5× speed ratio:

a) The filament thread-line does not include the friction element(discontinuous line in FIG. 12). The tension of the load cell isindicated as T_(o), that is, the tension that is assumed before thefriction element; and,

b) The filament is wrapped 180° on the friction element. The tensionread on the load cell is T₁, the tension after the friction element,also referred to as “available tension”.

The fiction coefficient can be calculated using the Euler formula:$\frac{T_{O}}{T_{1}} = {\mathbb{e}}^{\mu\quad\theta}$where μ is the friction coefficient.

Dynamic coefficient of friction (COF) results are listed in Table 28.Having low COF is desirable because high friction can often lead tofiber breaks in weaving and knitting applications. For some preferredfibers of the invention, the COF with polished metal can be relativelylow, as low as about 0.6 and less, preferably 0.5 or less, morepreferably 0.4 or less, and as low as about 0.3. Preferably, the COF isno higher than 1.0, more preferably no higher than 0.9 and mostpreferably no higher than 0.7. TABLE 28 Fiber 1 CL Fiber 4 CL Fiber 5 CLDynamic COF 0.521 0.433 0.389

Dynamic mechanical spectroscopy (DMS) is performed on an RSA IIIextensional rheometer (TA Instruments) to measure heat resistance. Abundle of 60 40-denier fibers is clamped between at both ends betweenfixtures separated by 10 mm. The sample is then subjected to successivetemperature steps from 25° C. to 200° C. at 3° C. per step. At eachtemperature the storage modulus, E′, is measured at a strain frequencyof 10 rad/s and a strain amplitude cycling between 0.1% and 5%. Aninitial static force of 5 g is applied to prevent slack in the sample.The test ends when the temperature reaches 200° C.

FIG. 20 shows the dynamic mechanical thermal response of Fiber 1 CL,Fiber 4 CL and Fiber 5 CL. The plot shows that the storage modulus forFibers 4 CL and Fibers 5 CL are higher than that of Fiber 1 CL.

Morphology of Fibers from Blends of Polymer Example 20 and Polypropylene

The morphology of the fibers is studied via ruthenium staining usingTransmission Electron Microscopy (TEM). The ruthenium stain does notstain the polypropylene. Fibers are trimmed with a razor blade toisolate the regions of interest. For perpendicular cross sections, thefibers are placed in a flat embedding mold and filled with Epofix epoxyresin and allowed to cure for 16 hrs at 40° C. For longitudinal crosssections, strands of fibers are first sonicated in methanol prior tostaining. The fibers are allowed to dry and placed on a glass slideusing double sided tape to allow them to hang freely from the sideopposite the tape. The fibers are prestained with RuO₄ vapors for 1 hourat ambient temperature. The staining solution is prepared by weighing0.2 gm of ruthenium (III) chloride hydrate (RuCl₃.H₂O) into a glassbottle with a screw lid and adding 10 ml of 5.25% aqueous sodiumhypochlorite to the jar. The glass slide containing the fibers is placedin the staining bottle in order to suspend the lose fibers about 1 inchabove the staining solution.

After staining, the fibers are removed from the jar and placed in abeaker of deionized water and sonicated for approximately 2 minutes toremove any residual RuO₄ from the sample. In order to orient the fibersso that sections could be collected longitudinally, a small piece of astained fiber is cut to approximately 3 mm in length and placed into aflat embedding mold. A piece of double sided tape is placed at the tipof the mold and the fiber is adhered to the tape in order to keep itstationary during the embedding process. A single fiber is embedded withEpofix epoxy and allowed to cure at 38° C. for 16 hours. Once cured, theblock is removed from the embedding mold and the double sided tapepeeled from the tip of the mold exposing the single fiber. The block istrimmed down to approximately about 0.1 mm to 0.3 mm with the fiber atthe center of the embedding epoxy.

Bright-field TEM images are collected on a JEOL JEM 1230 operated at 100kV accelerating voltage using Gatan 791 and 794 digital cameras. Theimages are post processed using Adobe Photoshop 7.0.

FIGS. 21 and 22 show TEM images of a sample of Fiber 4 cutperpendicularly and longitudinally, respectively, to the fiberorientation at low (about 3,000×) magnification. Unexpectedly, thepolypropylene component in the blend, seen as white areas in the TEMimages, is evenly distributed as nano-cylinders in the perpendiculardirection, and as elongated rods in the longitudinal direction. FIGS. 23and 24 show the corresponding images at a higher magnification (about30,000×). These images further showed that the polypropylene componentin the blend was in the nano-scale (<50 μm). This nano-scale polymerblend structure is novel and, not wishing to be bound by any particulartheory, it is believed that it may contribute to improved properties.

FIGS. 25 and 26 display TEM images at about 30,000× magnification of asample of Fiber 4 which was cut perpendicular to the fiber orientationdirection and compares the morphologies of the surface and centralsections, respectively, for the dispersion of the polypropylene domains.The images showed that there was no concentrated polypropylene on thefiber surface. There was no difference in morphology between the surfaceand central areas in a fiber cross section.

FIGS. 27 and 28 show TEM images at about 30,000× magnification of asample of Fiber 5 cut in perpendicular and longitudinal directions,respectively. It was seen that for a polypropylene with higher molecularweight, the nano-scale polypropylene phases were still observed.

Properties of Polymer Example 20 and Blends with Polypropylene used inFiber Examples Melt Strength vs Drawability at 200° C.

The melt strength and drawability for Polymer Example 20 and the blendwith polypropylene used in Fibers 6, 9 and 10 were measured at 200° C.The results are shown in FIG. 29. The blend showed higher melt strengththan Polymer Ex. 20 and the drawability was comparable.

Abrasion Testing

A sample of Polymer Ex. 20 and a sample of the blend used in Fiber 5were extruded into a rod with a 2.5 mm diameter. A copper wire waspressed on the rod and forced to scratch the surface repeatedly for anhour with 8000 cycles. The surfaces of the scratched rod samples areshown in FIGS. 30 and 31. As may be seen, both samples show someabrasion resistance, however, the sample containing polypropylene showsless surface damage than the sample of only Polymer Ex. 20.

TMA Indentation Results

TMA indentation measurements were conducted on crosslinked plaques whichwere compression molded. The penetration depth for a constant loadagainst temperature for Fibers 1, 4 and 5 is shown in FIG. 32. As may beseen, all three fibers perform well, however, Fibers 4 and 5 show animproved indentation resistance. This characteristic can provideimproved performance in processes such as cone dyeing where the fibercan be more resistant to scratches and breaks due to contact with hardyarns.

As demonstrated above, embodiments of the invention provide fibers madefrom a blend of unique multi-block copolymers of ethylene and α-olefinand propylene based polymers. The fibers may have one or more of thefollowing advantages: good abrasion resistance; low coefficient offriction; high upper service temperature; high recovery/retractiveforce; low stress relaxation (high and low temperatures); soft stretch;high elongation at break; inert: chemical resistance; UV resistance. Thefibers can be melt spun at a relatively high spin rate and lowertemperature. The fibers can be crosslinked by electron beam or otherirradiation methods. In addition, the fibers are less sticky, resultingin better unwind performance and better shelf life, and aresubstantially free of roping (i.e., fiber bundling). Because the fiberscan be spun at a higher spin rate, the fibers' production throughput ishigh. Such fibers also have broad formation windows and broad processingwindows. Other advantages and characteristics are apparent to thoseskilled in the art.

While the invention has been described with respect to a limited numberof embodiments, the specific features of one embodiment should not beattributed to other embodiments of the invention. No single embodimentis representative of all aspects of the invention. In some embodiments,the compositions or methods may include numerous compounds or steps notmentioned herein. In other embodiments, the compositions or methods donot include, or are substantially free of, any compounds or steps notenumerated herein. While some embodiments are described as comprising“at least” one component or step, other embodiments may include one andonly such component or step. Variations and modifications from thedescribed embodiments exist. The method of making the resins isdescribed as comprising a number of acts or steps. These steps or actsmay be practiced in any sequence or order unless otherwise indicated.Finally, any number disclosed herein should be construed to meanapproximate, regardless of whether the word “about” or “approximately”is used in describing the number. The appended claims intend to coverall those modifications and variations as falling within the scope ofthe invention.

1. A fiber obtainable from or comprising a blend of at least onepropylene based polymer and at least one ethylene/α-olefin interpolymer,wherein the ethylene/α-olefin interpolymer is characterized by one ormore of the following properties before crosslinking: (a) a Mw/Mn fromabout 1.7 to about 3.5, at least one melting point, Tm, in degreesCelsius, and a density, d, in grams/cubic centimeter, wherein thenumerical values of Tm and d correspond to the relationship:T _(m)>−2002.9+4538.5(d)−2422.2(d)²; or (b) a Mw/Mn from about 1.7 toabout 3.5, and a heat of fusion, ΔH in J/g, and a delta quantity, ΔT, indegrees Celsius defined as the temperature difference between thetallest DSC peak and the tallest CRYSTAF peak, wherein the numericalvalues of ΔT and ΔH have the following relationships:ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,ΔT≧48° C. for ΔH greater than 130 J/g, wherein the CRYSTAF peak isdetermined using at least 5 percent of the cumulative polymer, and ifless than 5 percent of the polymer has an identifiable CRYSTAF peak,then the CRYSTAF temperature is 30° C.; or (c) an elastic recovery, Re,in percent at 300 percent strain and 1 cycle measured with acompression-molded film of the ethylene/α-olefin interpolymer, and adensity, d, in grams/cubic centimeter, wherein the numerical values ofRe and d satisfy the following relationship when the ethylene/α-olefininterpolymer is substantially free of a cross-linked phase:Re>1481-1629(d); or (d) a molecular fraction which elutes between 40° C.and 130° C. when fractionated using TREF, characterized in that thefraction has a molar comonomer content of at least 5 percent higher thanthat of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer comprises the same comonomer(s) and has a melt index,density, and molar comonomer content (based on the whole polymer) within10 percent of that of the ethylene/α-olefin interpolymer.
 2. The fiberof claim 1, wherein the ethylene/α-olefin interpolymer is characterizedby an elastic recovery, R_(e), in percent at 300 percent strain and 1cycle measured from a compression-molded film of the ethylene/α-olefininterpolymer and a density, d, in grams/cubic centimeter, wherein theelastic recovery and the density satisfy the following relationship whenthe ethylene/α-olefin interpolymer is substantially free of across-linked phase:R_(e)>1481-1629(d)
 3. The fiber of claim 1, wherein theethylene/α-olefin interpolymer has at least one melting point, T_(m), indegrees Celsius and density, d, in grams/cubic centimeter, wherein thenumerical values of the variables correspond to the relationship:T _(m)>−2002.9+4538.5(d)−2422.2(d)² and wherein the interpolymer has aM_(w)/M_(n) from about 1.7 to about 3.5.
 4. The fiber of claim 1,wherein the ethylene/α-olefin interpolymer has a M_(w)/M_(n) from about1.7 to about 3.5, and the interpolymer is characterized by a heat offusion, ΔH, in J/g, and a delta quantity, ΔT, in degree Celsius definedas the difference between the tallest DSC peak minus the tallest CRYSTAFpeak, the ΔT and ΔH meet the following relationships:ΔT>−0.1299(ΔH)+62.81, for ΔH greater than zero and up to 130 J/g, orΔT≧48° C., for ΔH greater than 130 J/g, wherein the CRYSTAF peak isdetermined using at least 5 percent of the cumulative polymer, and ifless than 5 percent of the polymer has an identifiable CRYSTAF peak,then the CRYSTAF temperature is 30° C.
 5. The fiber of claim 1, whereinthe interpolymer has a density of from about 0.860 g/cc to about 0.895g/cc and a compression set at 70° C. of less than about 70%.
 6. Thefiber of claim 1, wherein the α-olefin is styrene, propylene, 1-butene,1-hexene, 1-octene, 4-methyl-1-pentene, 1-decene, or a combinationthereof.
 7. The composition of claim 1 wherein the propylene basedpolymer is present in an amount of between about 2.5 wt % to about 20 wt%.
 8. The fiber of claim 1, wherein the fiber is cross-linked.
 9. Thefiber of claim 8, wherein the fiber is cross-linked by photonirradiation, electron beam irradiation, or a cross-linking agent. 10.The fiber of claim 8, wherein the percent of cross-linked polymer is atleast 20 percent as measured by the weight percent of gels formed. 11.The fiber of claim 1, wherein the propylene based polymer is a highlycrystalline polypropylene.
 12. The fiber of claim 1, wherein the fiberis a bicomponent fiber.
 13. The fiber of claim 1, wherein the fiber hasa coefficient of friction of less than about 0.6, wherein theinterpolymer is not mixed with any filler.
 14. A fabric comprising thefiber of claim
 1. 15. The fabric of claim 14, wherein the fabric is anonwoven sheet comprising fibers made by solution spinning or meltspinning.
 16. The fabric of claim 14, wherein the fabric is elastic. 17.The fabric of claim 14, wherein the fabric is woven.
 18. The fabric ofclaim 14, wherein the fabric is knitted.
 19. The fabric of claim 18,wherein the fabric is circular knitted, warp knitted or flat knitted.20. The fabric of claim 14, wherein the fabric has an MD percentrecovery of at least 50 percent at 100 percent strain.
 21. A yarncomprising the fiber of claim
 1. 22. The yarn of claim 21, wherein theyarn is covered.
 23. The yarn of claim 22, wherein the yarn is coveredby cotton yarns or nylon yarns.
 24. A fiber obtainable from orcomprising a blend of at least one propylene based polymer and at leastone ethylene/α-olefin interpolymer, wherein the ethylene/α-olefininterpolymer is characterized by one or more of the following propertiesbefore crosslinking: (a) having at least one molecular fraction whichelutes between 40° C. and 130° C. when fractionated using TREF,characterized in that the fraction has a block index of at least 0.5 andup to about 1 and a molecular weight distribution, Mw/Mn, greater thanabout 1.3; or (b) an average block index greater than zero and up toabout 1.0 and a molecular weight distribution, Mw/Mn, greater than about1.3.
 25. The fiber of claim 24, wherein the α-olefin is styrene,propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 1-decene,or a combination thereof.
 26. The fiber of claim 24 wherein thepropylene based polymer is present in an amount of between about 2.5 wt% to about 20 wt %.
 27. The fiber of claim 24, wherein the fiber iscross-linked.
 28. The fiber of claim 27, wherein the fiber iscross-linked by photon irradiation, electron beam irradiation, or across-linking agent.
 29. The fiber of claim 27, wherein the percent ofcross-linked polymer is at least 20 percent as measured by the weightpercent of gels formed.
 30. The fiber of claim 24, wherein the propylenebased polymer is highly crystalline polypropylene.
 31. The fiber ofclaim 24, wherein the fiber is a bicomponent fiber.
 32. The fiber ofclaim 24, wherein the fiber has a coefficient of friction of less thanabout 0.6, wherein the interpolymer is not mixed with any filler.
 33. Afabric comprising the fiber of claim
 24. 34. The fabric of claim 33,wherein the fabric is a nonwoven sheet comprising fibers made bysolution spinning or melt spinning.
 35. The fabric of claim 33, whereinthe fabric is elastic.
 36. The fabric of claim 33, wherein the fabric iswoven.
 37. The fabric of claim 33, wherein the fabric is knitted. 38.The fabric of claim 37, wherein the fabric is circular knitted, warpknitted or flat knitted.
 39. The fabric of claim 33, wherein the fabrichas an MD percent recovery of at least 50 percent at 100 percent strain.40. A yarn comprising the fiber of claim
 24. 41. The yarn of claim 40,wherein the yarn is covered.
 42. The yarn of claim 41, wherein the yarnis covered by cotton yarns or nylon yarns.
 43. A method of making afiber or fabric, comprising: melt mixing a blend of at least onepropylene based polymer and an ethylene/α-olefin interpolymer; andextruding the blend into a fiber, wherein the ethylene/α-olefininterpolymer is characterized by one or more of the following propertiesbefore crosslinking: (a) a Mw/Mn from about 1.7 to about 3.5, at leastone melting point, Tm, in degrees Celsius, and a density, d, ingrams/cubic centimeter, wherein the numerical values of Tm and dcorrespond to the relationship:T _(m)≧858.91−1825.3(d)+1112.8(d)²; or (b) a Mw/Mn from about 1.7 toabout 3.5, and a heat of fusion, ΔH in J/g, and a delta quantity, ΔT, indegrees Celsius defined as the temperature difference between thetallest DSC peak and the tallest CRYSTAF peak, wherein the numericalvalues of ΔT and ΔH have the following relationships:ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,ΔT≧48° C. for ΔH greater than 130 J/g,  wherein the CRYSTAF peak isdetermined using at least 5 percent of the cumulative polymer, and ifless than 5 percent of the polymer has an identifiable CRYSTAF peak,then the CRYSTAF temperature is 30° C.; or (c) an elastic recovery, Re,in percent at 300 percent strain and 1 cycle measured with acompression-molded film of the ethylene/α-olefin interpolymer, and adensity, d, in grams/cubic centimeter, wherein the numerical values ofRe and d satisfy the following relationship when the ethylene/α-olefininterpolymer is substantially free of a cross-linked phase:Re>1481-1629(d); or (d) a molecular fraction which elutes between 40° C.and 130° C. when fractionated using TREF, characterized in that thefraction has a molar comonomer content of at least 5 percent higher thanthat of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer comprises the same comonomer(s) and has a melt index,density, and molar comonomer content (based on the whole polymer) within10 percent of that of the ethylene/α-olefin interpolymer.
 44. The methodof claim 43, further comprising forming a fabric from the fiber, whereinthe fabric is substantially free of roping.
 45. A composition comprisinga blend of a propylene based polymer and at least one ethylene/α-olefininterpolymer, wherein the ethylene/α-olefin interpolymer ischaracterized by one or more of the following properties beforecrosslinking: (a) a Mw/Mn from about 1.7 to about 3.5, at least onemelting point, Tm, in degrees Celsius, and a density, d, in grams/cubiccentimeter, wherein the numerical values of Tm and d correspond to therelationship:T _(m)>−2002.9+4538.5(d)−2422.2(d)²; or (b) a Mw/Mn from about 1.7 toabout 3.5, and a heat of fusion, ΔH in J/g, and a delta quantity, ΔT, indegrees Celsius defined as the temperature difference between thetallest DSC peak and the tallest CRYSTAF peak, wherein the numericalvalues of ΔT and ΔH have the following relationships:ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,ΔT≧48° C. for ΔH greater than 130 J/g, wherein the CRYSTAF peak isdetermined using at least 5 percent of the cumulative polymer, and ifless than 5 percent of the polymer has an identifiable CRYSTAF peak,then the CRYSTAF temperature is 30° C.; or (c) an elastic recovery, Re,in percent at 300 percent strain and 1 cycle measured with acompression-molded film of the ethylene/α-olefin interpolymer, and adensity, d, in grams/cubic centimeter, wherein the numerical values ofRe and d satisfy the following relationship when the ethylene/α-olefininterpolymer is substantially free of a cross-linked phase:Re>1481-1629(d); or (d) a molecular fraction which elutes between 40° C.and 130° C. when fractionated using TREF, characterized in that thefraction has a molar comonomer content of at least 5 percent higher thanthat of a comparable random ethylene interpolymer fraction elutingbetween the same temperatures, wherein said comparable random ethyleneinterpolymer comprises the same comonomer(s) and has a melt index,density, and molar comonomer content (based on the whole polymer) within10 percent of that of the ethylene/α-olefin interpolymer; wherein thepropylene based polymer is present as nano-cylinders.
 46. Thecomposition of claim 45 wherein the propylene based polymer is presentin an amount of between about 2.5 wt % to about 20 wt %.